I bought them both. Here's the scoop.
I will make my comparison of the 2 in point form:
Gameplay:
2K- Same gameplay as always. No complaints. It is what it is.
EA- Skill Stick makes you want to get in clear to shoot and score as opposed to trying for the perfect one timer. You do feel reward for scoring. It's refreshing but the gameplay is very raw. Defensive play is terrible. Graphics:
2K- Amazing. I can't say enough about 2K in this area. The play is smooth and slick.
EA- I disagree with the reviews out there that claim EA's hockey looks great. It doesn't. It's OK but compared to 2K it pales. The game plays a tad choppy and the collisions are poor. I can't understand why the reviews contradict this. It's just not that good.
Sound:
2K- Again, top notch. The orchestral soundtrack is weird though.
EA- Falls short. It's decent but some of the sounds are off. (hits, etc)
Online Play and Dynasty:
I will not comment on either as I have not ventured that far yet.
In conclusion, if I could recommend one over the other, i would say go with EA if the 2K engine is becoming boring for you. EA will take over the hockey world with their next offering. This first one is raw and just needs some polish. 2K is the safe choice, however, I must say, the future looks bright as EA has definetely changed the hockey landscape.