Let me preface by saying this is MY opinion so if you don't agree with something that I said please don't tell me I am wrong, its the way I feel so it cant be wrong to me ( Oh wow I sound like my wife!!!!! 
). So I have had both phones the S6 for a little over a month and G4 since release day. Hopefully this will help some people who are still on the fence or who are wondering the differences between these 2 flagships
SCREEN:
This is when the S6 shines. Its easily the best screen on a smartphone I have seen, IF YOU LIKE THE AMOLED type of displays this is hands down the best. There is really nothing negative you can say, If you dont like the "punchy" colors you can change the display settings. If I didn’t ever see the S6 display and only saw the G4 then the G4 would have won that title. I have had the Note4, HTC M8 and the Nexus 6. A good way of looking at the G4 screen is it would be the middle setting of the Samsung settings. Not quite as “punchy” as the amoled cinema setting but more “punchy” than the basic. Im a huge fan of the amoled displays and the LCD is the one that comes closest to reproducing the contrast you see on Samsung displays. The S6 gets extremely bright in outdoor auto settings, the G4 not as bright but bright enough you will not complain.
BATTERY LIFE:
As good as the S6 screen is that’s how BAD the battery life is. I know some people have had good battery life with the S6 unfortunately I was not one of them. I tried everything installing several different battery saving software, greenfy etc…. Nothing worked! I would reset the cache partition about every 2-3 days (will get into that later). It could have been I had a defective device but seriously doubt it With the S6 I ALWAYS found myself looking at the battery and closing apps, running sweep master, doing battery saving things! And yes I did all the tips and tricks mentioned in these forums and other forums. Yes I know the quick charging is fast WHO CARES!!!! I want my damn battery to make it at least a day! My experience with the G4 was complete opposite, I had the same apps same things running and the G4 would get me through the day with ease, I can even turn up my brightness and turn on location settings to high. It was truly a night and day difference. I never once when I left my house with a full charge had to worry about not having enough to make it the whole day. Bottom line is the G4 battery was way better FOR ME than the S6.
Software/Performance
Oh Samsung when are you going to get this right???? I wanted to like the new Touch Wiz sooooooo bad. The first few days I had the phone it was AMAZING just flawless performance ZERO lag everything was snappy and almost instant. Then a week went by, then 2 then 3 and my phone was acting like a old Pentium CPU that couldn’t handle all the stuff you put on it. There were times when I would hit my home button and after what seemed like 5 minutes but was actually @30 sec later my home screen would show up! I think this is called redraw? From my experience if you add widgets and load up your screens the phone almost becomes a brick I would have to run my screens like a Icrap and have nothing on them. This is where every 2-3 days I would reset the cache partition and it would run fine then start acting up again. I read that this could possibly be a lollipop problem or the way Samsung handles memory. I tried it all, turning on developer options and limiting background process then went back to standard, nothing worked. I can honestly tell you that this phone went from being almost perfect to almost unusable! And yes I tried Nova, M launcher and every other launcher and got the same result. This really sucks because I really liked touch wiz and the new themes.
Once again COMPLETE opposite experience with the G4, this phone has run the way the S6 did when it was running flawlessly. I have all my widgets hell I even have Live wallpaper and it runs like nothing it on it. I know its weird because I read that peoples G4 is laggy etc. I have 0 need to want to add a launcher at this point. The G4 has acted the same as it was day 1. Very impressed with the LG skin and the optimization , goes to show you its not the sheer numbers but how the software and chip work together, and I hate to admit it Icrap has been proving that for years.
Camera
I LOVE THE S6 camera it is amazing! Some of the shots I took with it did not look like a came from a cell phone camera, the colors the simplicity in the options( even though there was a lot of them ) were almost perfect! There really is nothing wrong I can say about this camera, in my eyes the best by far on any smartphone. The G4 COULD BE better, but im not a damn photographer I don’t know what the heck shutter speed iso blah blah blah is. Im sure if you took the time to study all that you can do with the G4 camera it would be better than the S6. But it you were taking just straight shot for shot without all the adjustments the S6 has a better camera. Both cameras are great and are easily 1 and 2 in my opinion on smart phone cameras
Overall/ Summary
I am a Samsung lover! This is the first LG phone I’ve had and I am VERY impressed IF and that’s a BIG IF the S6 ran like it did the first few days I got it, it would be the better phone, but the fact I have to baby it and HOPE it runs good is a big turnoff and the fact for me the battery was horrible and that sealed the deal . The G4 been flawless from day one ZERO lag all day battery and then some I am really impressed with this phone. BUT once the s6+ is released if the rumors are true I will be switching back( the joys of Tmobile new jump on demand) to see if the addition of 5.1 and hopefully Samsung learned and made the phone run smoother regardless If its day 1 or 30. Its to bad the S6 ran the way it did for me. If all things being equal and both phones ran the same way with no lag and all day battery the S6 would be my choice. But for me that was not the case. And LG has done one hell of a job with the G4, it’s a great phone and is my choice for my daily driver…………………for now!!! ( s6+ Note 5)
). So I have had both phones the S6 for a little over a month and G4 since release day. Hopefully this will help some people who are still on the fence or who are wondering the differences between these 2 flagshipsSCREEN:
This is when the S6 shines. Its easily the best screen on a smartphone I have seen, IF YOU LIKE THE AMOLED type of displays this is hands down the best. There is really nothing negative you can say, If you dont like the "punchy" colors you can change the display settings. If I didn’t ever see the S6 display and only saw the G4 then the G4 would have won that title. I have had the Note4, HTC M8 and the Nexus 6. A good way of looking at the G4 screen is it would be the middle setting of the Samsung settings. Not quite as “punchy” as the amoled cinema setting but more “punchy” than the basic. Im a huge fan of the amoled displays and the LCD is the one that comes closest to reproducing the contrast you see on Samsung displays. The S6 gets extremely bright in outdoor auto settings, the G4 not as bright but bright enough you will not complain.
BATTERY LIFE:
As good as the S6 screen is that’s how BAD the battery life is. I know some people have had good battery life with the S6 unfortunately I was not one of them. I tried everything installing several different battery saving software, greenfy etc…. Nothing worked! I would reset the cache partition about every 2-3 days (will get into that later). It could have been I had a defective device but seriously doubt it With the S6 I ALWAYS found myself looking at the battery and closing apps, running sweep master, doing battery saving things! And yes I did all the tips and tricks mentioned in these forums and other forums. Yes I know the quick charging is fast WHO CARES!!!! I want my damn battery to make it at least a day! My experience with the G4 was complete opposite, I had the same apps same things running and the G4 would get me through the day with ease, I can even turn up my brightness and turn on location settings to high. It was truly a night and day difference. I never once when I left my house with a full charge had to worry about not having enough to make it the whole day. Bottom line is the G4 battery was way better FOR ME than the S6.
Software/Performance
Oh Samsung when are you going to get this right???? I wanted to like the new Touch Wiz sooooooo bad. The first few days I had the phone it was AMAZING just flawless performance ZERO lag everything was snappy and almost instant. Then a week went by, then 2 then 3 and my phone was acting like a old Pentium CPU that couldn’t handle all the stuff you put on it. There were times when I would hit my home button and after what seemed like 5 minutes but was actually @30 sec later my home screen would show up! I think this is called redraw? From my experience if you add widgets and load up your screens the phone almost becomes a brick I would have to run my screens like a Icrap and have nothing on them. This is where every 2-3 days I would reset the cache partition and it would run fine then start acting up again. I read that this could possibly be a lollipop problem or the way Samsung handles memory. I tried it all, turning on developer options and limiting background process then went back to standard, nothing worked. I can honestly tell you that this phone went from being almost perfect to almost unusable! And yes I tried Nova, M launcher and every other launcher and got the same result. This really sucks because I really liked touch wiz and the new themes.
Once again COMPLETE opposite experience with the G4, this phone has run the way the S6 did when it was running flawlessly. I have all my widgets hell I even have Live wallpaper and it runs like nothing it on it. I know its weird because I read that peoples G4 is laggy etc. I have 0 need to want to add a launcher at this point. The G4 has acted the same as it was day 1. Very impressed with the LG skin and the optimization , goes to show you its not the sheer numbers but how the software and chip work together, and I hate to admit it Icrap has been proving that for years.
Camera
I LOVE THE S6 camera it is amazing! Some of the shots I took with it did not look like a came from a cell phone camera, the colors the simplicity in the options( even though there was a lot of them ) were almost perfect! There really is nothing wrong I can say about this camera, in my eyes the best by far on any smartphone. The G4 COULD BE better, but im not a damn photographer I don’t know what the heck shutter speed iso blah blah blah is. Im sure if you took the time to study all that you can do with the G4 camera it would be better than the S6. But it you were taking just straight shot for shot without all the adjustments the S6 has a better camera. Both cameras are great and are easily 1 and 2 in my opinion on smart phone cameras
Overall/ Summary
I am a Samsung lover! This is the first LG phone I’ve had and I am VERY impressed IF and that’s a BIG IF the S6 ran like it did the first few days I got it, it would be the better phone, but the fact I have to baby it and HOPE it runs good is a big turnoff and the fact for me the battery was horrible and that sealed the deal . The G4 been flawless from day one ZERO lag all day battery and then some I am really impressed with this phone. BUT once the s6+ is released if the rumors are true I will be switching back( the joys of Tmobile new jump on demand) to see if the addition of 5.1 and hopefully Samsung learned and made the phone run smoother regardless If its day 1 or 30. Its to bad the S6 ran the way it did for me. If all things being equal and both phones ran the same way with no lag and all day battery the S6 would be my choice. But for me that was not the case. And LG has done one hell of a job with the G4, it’s a great phone and is my choice for my daily driver…………………for now!!! ( s6+ Note 5)
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