It's better on Heisman, but I think Xbox Live for 360 defaults to All-American on online play. If you personally invite a friend you can switch it over to Heisman in the game set-up, but the game won't count towards your online record.
I just play one or two years of dynasty then it gets boring. I like playing online. I struggled with Bama first year, but blew out everyone else with State.
Me vs CPU on Heisman avg score prolly like 45-17. Online avg score about 55-48. Online is a differ animal.