I'm gonna get to see the Blue one this weekend (hopefully), and the Green one after new years. I'd probably have a tough time deciding...I agree w/ Jason - having all characters represented makes the most sense for the theme. Metallic blue just seems really cool looking...and I have a feeling the mirrored backglass will have a totally different impact in person than in pictures. However, I hate that f*cking jumpkick pose of Black Widow that's all over the entire game.
Hulk is just Hulk, which is less Avengers-y....but - he IS the main toy of the game. So in that sense I don't think being totally Hulked out is odd, compared to TF which DID look odd as one faction, IMO - since the game design itself was split down the middle. Also, when you see his animation on the green DMD, it just looks "right". The other characters look weird in green, but hey, whatcha gonna do.
So....yeah...I just gave you zero useful info...lol...you've seen them both in person so you know what's up.