I gave it a 7. I liked it, it was cheesy, but in a good way. But it didn't have much of a story. And there wasn't an obvious 'saving of the city/country/world', the final fight seemed anti-climatic, like it wa s agrudge fight, not very FF, IMO. Also when they were first exposed to the public, they were cheering them, especially the Thing, as heroes, when he was the initial cause of the problem. I didn't mind Jessica Alba as Sue, but the writer did his best to get her as naked as possible as often as possible. That was sillly, and not Alba's fault.
On the other hand, if it were up to me, I would be trying to get Jessica naked as often as possible, too...
I did like it though, for the same reason I liked the Spider-Man and X-Men movies: they captured the characters well (well, excpet Doom, but then they usually mess with the villian big time).
Decent movie, good super-hero movie, better than I expected from the crap trailers.