I really like Fanball, from a price/performance stand-point. It's really customizable, user friendly, and looks really good. It's also among the cheapest out there, at $70. I don't however care for My Fantasy League. It just feels cumbersome, it's not very refined. Far less use friendly in my opinion.
AOL is the exact same as Fanball and is completely free. I researched the free sites (Yahoo, ESPN and Fox) this year and AOL offered alot more options and features, IMO. The Live scoring is free and if tonight's game is any indication, the live scoring is as good I've seen. Yahoo is a very good option as well, but while there is no site fee, the live scoring is not free. Yahoo doesn't have as many features/flexibility as AOL, but the interface is very simple and user friendly. I chose AOL for our league since I thought free live scoring was important. In my limited sampling of ESPN it had neither the features or user-friendliness of Yahoo, while FOX has a bad rep as being unstable and lacking reliability, I would stay away.