Well I got the game during the current PS4 sale. Actually I got a physical copy for $10 used, but it was the same time anyway and I bought the DLC. It's pretty much what I expected from everything I've seen and heard. Should be more polished in models, lighting, music, voicework (I can't tell if Gamora's VA can't sound enthusiastic or if it was the director), menu options (no music select, only basic Training Mode), HUD. Also should've had better marketing and focused more on character interactions than some big plot! Gonna blame Disney Marvel for story and story marketing, though. But it's pretty fun and there's a high amount of freedom. I think the roster's fine, the 20-some count is totally okay especially with the thought-out gameplay and already having a lack of polish budget, the only character I would replace is Nemesis (I'd put in Asura).
I might play X/Marvel. Zero has so much freedom and options it's crazy but X has cool stuff. I like having a long-lasting projectile like his wind boomerang for Active Switch. Haven't really seen Captain Marvel, maybe it's just a case of "Ultron's a safer pick" but she's cool too.