Friend of mine has a Nexus, which is a nice phone, but is half the processing power of the Photon. I pondered the Nexus for a while, but after I actually held and operated the Photon, I new it was for me.
Some of the decision should be based on how are you going to use it? My friend mostly texts with his phone. I use mine as a work companion, calendar, GPS, messaging,...music player as well.
The exceptional signal on the Photon was also a big selling point for me. I get a strong signal where I previously was on roaming. I live and travel on the outskirts of a large city and I think the strong signal has a lot to do with the great battery life.
I previously had a EVO 4G and EVO 3D and the photon's battery life is much better.
There is not much I would change about the photon. The camera is not great, but I don't really care.