One of the biggest factors to the new football games being enjoyable are that they run at 60fps. Of course we've only seen footage on the Xbox 360 and it is very apparent that it really does make a significant difference.
1UP however has confirmed that the PS3 versions of Madden 08, NCAA Football 08, and All-Pro Football 2K8 will only run at 30fps. Only the 360 versions of those games will run at 60fps. That is a HUGE deal.
Now not only does the 360 have the advantage with rumble, achievements, and larger online player base, but also fps. There really isn't any question which version people should be going with this year.