Think about the last generation PS2 was the winner but there was that little saying "If a game is on all consoles get it for Xbox" but yet the PS2 was considered the winner. That saying was started because Xbox's hardware was better and it's online. The reason 360 is being called better right now is because it has a massive library of games and it's hardware is better but 5-6 years down the line when games are pretty much dead for the consoles I think PS3 will be better because of what we saw last generation.
Now I am not saying it will be the same this generation because of a lot of things:
1. Wii is a lot bigger factor than GameCube was
2. We have reached a point where software is no longer 90% of a consoles success
3. PS3 is loosing a lot of exclusives although it is retaining some