I come to this forum because I want to be convinced to get the N4 over the S4.
I was in the same position as you 3 days ago. I decided to go with the N4. Having used Samsung's products, I can tell you the Nexus 4 is dramatically easier to use. Even for simple stuff like making calls.
Samsung always hits a home run with their hardware (CPU/RAM). They always have great displays, they always have SD and removable battery. The only drawback to buying their products is that you are stuck with touchwiz. It is clunky and gaudy and annoying to use (though Sense is worse). Of all the skinned UIs though, you are most likely to get OS updates through them though. Good luck getting that with HTC.
I was at the store yesterday and had the S4 pulled and ready to pay and I decided to walk out of the store and think. I just am severely bothered by the bloat and overlay (touchwiz) of the S4.
As well you should be. But it could be worse. HTC
loves bloat more than anyone. Vanilla Android has been a dream for me...well worth living without SD or a removable battery.
There are some things on the s4 that are superior to the N4 such as battery life (i think?)
Yes, but not for the reason you think.
It really does not matter what the battery life on the S4 is, because you can always just upgrade the battery. My roommate still has his S3 with extended battery, and that thing will go forever on a change. With the N4 you will just have to hope the embedded battery is enough.
The benefits of the N4 to me are: I'd get updates asap. No overlay or bloat (minimal bloat at least). I highly value the vanilla feel of the N4 and the ability to get updates faster. It is probably good enough to get me by until the next nexus comes out. I am a tech geek to the extreme and I like having the latest and greatest but at this point I'm not sure the S4 offers me much over the N4. The camera isn't a huge deal to me as I always have my Fuji with me. I'm just mainly concerned with screen, battery life and feel of the phone.
The N4 has the best display of any phone right now IMO, with the possible except of the One. It has deep blacks (as deep as I have ever seen on LCD) and very bright whites. It is the easiest to see in the sun of any phone I have ever used. The Camera is comparable to the S3's, but it does better macro (really good actually). The N4's low-light could be better, and it does not like high contrast scenes (like sunsets). The difference between 1080p and 720p (really 768p) is so minimal that only the biggest graphics geeks will notice. the N4 display is only 6 pixels shy of the 326ppi used in retina displays...despite being physically larger than the S3. And of course there are no pentile artifacts (though at 1080p you will not see them on the S4 either)
On battery life, you will be screwed. I am just going to buy a power pack myself. There are no after market batteries that I know of. The battery is not too hard to remove and replace yourself, but no one is making upgraded versions yet. It has no SD support, but you can plug thumb drives into it via USB OTG.
The formfactor feels high quality if a bit delicate. You will probably want a case for it. It is very thin if you are into that (I'm not). The build quality feels to me comparable to an Apple product, which is to say very very good. I love the curved glass on the front. Like the iPhone it has glass on the back...it is the latest gorilla glass, but still...