Hopefully the OP has made a decision by now, but I'll throw my 2 cents out there for any iPhone users considering a switch. I'll start by saying that I LOVE Apple products. I own a Mac and love it. I have AppleTV and love it. I have a 2TB Apple Time Capsule and love it. I had an iPod (the 1st gen that played video) and I loved it. My 1st Gen iPad still works great. I also had an iPhone 3GS and 4S and I loved both of them as well. Great company, great products. And let's face it, they came up with some next level ish when they introduced the iPod and then the iPhone. Props to the OG of smartphones.
That said, I am in-farging-love with my Note 4. Sure, we're still in the honeymoon stage because I've only had it for a week, but it's giving me the Android experience that I was hoping for when I switched last year and got the Galaxy S5. The Note 4 is fantastic if you're looking for a smartphone on steroids.
What makes Apple so great with computers is also what hurts it with phones and tablets, imo. An Apple computer is pretty much built 100% by Apple. They design the OS, they get all of the hardware and components that will function the best with their OS and then they put it in their own case. But when it comes to a Windows PC, Microsoft only supplies the OS and then different companies like Dell, HP, Sony, Samsung, etc, all make their own little tweaks and adjustments. They use different processors and components and screens and cases. No Windows PC is actually designed to run the Windows OS at 100% of it's potential and that makes for varying levels of enjoyment or frustration when operating a Windows PC....depending on the manufacturer and model of the PC you are using.
Now, you'd think that that concept would carry over to phones and tablets. You'd be wrong. The "openness" of Android is what makes it so different, and in many ways, better than iPhone. Each cell phone manufacturer has their own features and functions that they can put into their Android phones. 1 company might focus on putting in a crazy good camera (I think it's the Nokia Lumina that went with an absurd 40something mexapixel camera), while another company might want to have a superior voice command system in place. What drew me to Samsung was their multitasking features. I know that other phones have them as well, but the Note 4 seemed like a phone that I could easily integrate with my job and be productive when I'm out of the office, and still be able to use many of those same features for my own personal enjoyment and entertainment.
My Mac doesn't really do anything that a Windows PC can't do. They both have all of the same functions. I prefer Mac because it offers a significantly more stable operating system and they have a much longer shelf life than a Windows computer. But when it comes to phones, there are literally dozens upon dozens of things that I can do with my Note 4 that I could never do with my iPhone. Yes, any Android phone you get is going to be a little more "glitchy" than the iPhone, but iPhone is still very limited in what you can do with it. My g/f got the iPhone 6 a few months back and other than the bigger screen, I honestly don't see very many improvements in the actual capabilities of the phone. It's a great phone, don't get me wrong. You'll probably never hear me say anything bad about an Apple product. But just as iPhone was some next level ish when it was introduced, the Android line of phones, and specifically the Note 4, have taken things to a whole other level.
There are some downsides. Each cell phone carrier is going to put their own bloatware all over your phone and you can't get rid of it, but you can disable it and hide the app icons. Each manufacturer is also going to have a few of their own apps that you might find useless but can't get rid of either. It's like buying a new PC and booting it up and having Netscape and AOL icons on your desktop (are those even a thing anymore? That's how long I've been with Mac). Another downside is that if you are heavily invested in iOS apps then you're going to have to buy them all over again.
The upsides (outside of the Note 4 just being pretty awesome) are the removable battery and expandable memory. The only reason I upgraded my iPhone 3GS to the 4S was because my battery took a dump. If the battery in my Note 4 goes bad, that will suck, but I can replace it for like $15-20. I also love having the expandable memory slot for a micro sd card. 32 gigs internal storage and you can add up to 128 gigs with a memory card. Once you buy an iPhone, you're stuck with whatever storage capacity you decided to go with. Lastly, the phone charges with a standard micro USB cord. I've got a gazillion of those cables around my house thanks to various devices I've bought over the years. If there's one thing that Apple is really being a d*ck about, it's wanting to have their own unique charging cable. 1st it was the 30 pin, now it's the lightning cable (or whatever they call it). Either way, it's a pita. There. That's the 1 bad thing I'll say about Apple. Their charging cables blow.
If Apple were to ever release a "professional grade" iPhone that mimicked the Note 4, I'd probably jump on it in a heartbeat, but for now (and the next 23 months of my contract), I'll be sticking with the Note.