My MHR game at my local game store is going quite well. We had 8 people the first time, which was really slow, but the game went better with 6 people last night.
We have about an equal mix of original characters and Marvel characters. The canon characters are Iron Man, Thor, Spider-Man, and Shadowcat.
Kitty Pryde has been probably the most effective so far, stressing out the most villains through mental or emotional stress. We used mental stress to represent her ability to outmaneuver Bulldozer of the Wrecking Crew, sending him falling off Stark Tower Los Angeles. (It could have been a complication, but the mental stress made the most sense.)
I did have some fun with Thunderball targeting Lockheed and knocking him out of the fight. WHAM! Poor dragon...
One of the players grabbed the Wrecker's crowbar once the Wrecker was down, and used it to depower Piledriver's invulnerability. He had no particular mystic abilities, but I let him take a roll anyway and he did good on it, so it worked. (I'd pointed out before that the Wrecker is tougher when he's not sharing his power with the 'Crew.)
The Wrecking Crew are a very interesting team to throw at new players, since their Invulnerability SFX makes all of them immune to physical stress -- thus requiring out-thinking them and clever play through alternate stress types and complications!
The game continues to be really enjoyable with a mix of characters and players who dig the narrative-first style of play that MHR promotes.