[Grim Goblin]

-Background-

616

-Captain America: Both versions are pretty similar, but the movies, like the 616 version use vita rays as part of the process to create super-soldiers.

-Thor: Nobody questions his otherworldly origins, the existence of Asgard, or his sanity.

-Iron Man: Injured and captured by terrorists. Creates a chest piece that keeps him alive and a suit of armor to escape.

-Black Widow: Again, both versions are very similar, with the whole "former Russian spy turned SHIELD agent and superhero". But unless she turns traitor in a sequel, so far it's closer to 616 history.

-Loki: Same reasons as Thor, I guess.

Ultimate

-Hawkeye: pretty much the same as the Ultimate version, basically a highly specialized SHIELD agent who joins the team.

-Nick Fury: Again, a direct translation from the Ultimate version.

-Hulk: Resulted from an attempt to recreate the super-soldier formula.

-Personality-

616

-Captain America: Not a jerk.

-Thor: lofty attitude, but without the constant political or social critique that the Ultimate version had during the first couple of volumes.

-Hulk: Not a horny cannibal. He smashes...that's it.

-Black Widow: Could easily go both ways, since both versions are so similar. But I'm putting here based on the obvious attraction she displayed towards hawkeye in the movie.

Ultimate

-Nick Fury: Smooth talker and badass. Not the gruff old warhorse he is in the 616 universe.

-Hawkeye: a few quips aside, he's definitely more serious and calculated than the 616 version. Although there is an underlying attraction to Black Widow which is definitely 616 based.

-Iron Man: Tony has historically been more serious in the 616 version, as opposed to the easy going attitude of the Ultimate and movie version.