I actually tried this game with a friend yesterday.
It was really fun, felt like each character was worth their points and had a use.
I really liked how the flying guys actually felt fast and mobile. I also feel like they captured the feel of the characters.
Played Avengers starter vs guardians. Thor and Iron man flew around dishing out the pain, and black widow/Captain america were accomplishing objective and doing a ton of tactical stuff.
Throwing building around with Thor was really fun.
Rocket climbing on walls and sniping people was pretty cool as well.
I also like the flavour of the damage for instance as Ironman gets damaged he really loses effectiveness near the end he has penalties to defense and cannot fly (because his suit is being destroyed). whereas Captain America actually gains some bonuses when he is about half health (to represent his endurance and resolve), then gets negatives when almost dead.
Also based on the models out looks like a normal size game will net 6-7 models depending on costs.
Anyone who has played warmachine or guildball will jump into it very easily
Edit: I also liked how some powers had overload abilities, but you couldn't combine those with the "boost", so it gives an interesting choice of do I want to make this attack more accurate? or make it an AEO, or more damage, or stun them (depending on the power)