Upgrading from a Nexus 4

[tengarp]

Hey guys, I am eligible for an upgrade from my Nexus 4 from t-mobile and I was originally going to go with the nexus 6, but when I found out that stuff like the battery life weren't all that great, I decided I would look more widely at all the other options out there. I would like some advice though on which phone to upgrade to, i don't care that much about processing power and screen resolution since most phones nowadays run perfectly fine at 1080p and with whatever processor they have. I do however want a decent battery life, 4 or so hours, and a good camera. The camera on my phone right now is really terrible so something better would be nice. Also android os is a must and i'll probably install cyanogen mod on it if it isn't a nexus device. Some phones I'm thinking of are the Note 4, s5, one m8, nexus 6 maybe if it is good though it might be too big for me I would prefer a phone more the size of a m8. Any other recommendations are welcome, thanks for the help!

[Aniallation]

Are you planning to get a device through a continued contract with your carrier? Or would options outright like the OPO and Nexus 5 be worth considering?

[Mew]

You only want 4 hours of battery life? As in gaming? Only the gs5 is able to deliver 4 hours. http://anandtech.com/show/8242/the-oneplus-one-review/3 look at the Gfxbench 3 battery life.