I must say go the PS3 route as well, I have never been so infatuated with a piece of electronic equipment in my home theater in such a long time.
The thing is absolutely beautiful, and (knock on wood) bulletproof to boot!
I will admit I was a 360 guy, and hated all over the Sony product. I was looking into Blu-ray and there really is only one option, the PS3... So I bought one, and I am not looking back, kind of like Apple Vs. PC, one is sexy and does what you want and beyond (PS3), the other..well...it does what it wants to you...
I know the comparison wasn't for gaming consoles, but I do not own a ATV setup so I cannot comment on that. Do whats best for your eyes and mind, buy the master at what it does right now. Sony all the way.
I have more reasons, but I tried to make this short and sweet.
Robert