Yeah, the screen size is what was bad about it. I didn't mind it when I had my 3G, but after getting the S3, holy crap did it change everything haha.
But after a year, or 2, the S3 started becoming a hungrier eater of the battery. I remember driving with my friend to Toronto downtown, and I was using my S3 as a nav. It's just a 1 hour drive on the highway, and it ate 50% of it's battery life. It was fully charged!
With my Nexus 5, I did the same thing, but it only used 15% of it. I also used it again to drive back home. This thing did not die till midnight.
The LG G4 will be my next phone. But at the same time, I love the Nexus experience, and I want a Nexus phone lol.