I have been a long-time Marvel Legendary collector, and was told by a few friends about Marvel Champions in the past, but had decided not to invest in a new game/collection. But after seeing the game appear in the top of the solo-game list, and seeing as I live thousands of miles away from family and friends, I decided to take the jump and try it.
After a few games (3 solo, 1 two-player game with a local friend), I can confidently say that this game will replace Legendary completely for me. Preparing/Building a deck for a specific character (and their allies), and then playing with it against a villain feels much better than the deck-building during play that happens in Legendary.
The clever dual-purpose of all cards (They can be used for their effect, such as events, allies, upgrades, or as resources to pay for the other cards), including the villain deck is incredibly clever, and gets rid of one of my annoyance with the land cards in MTG.
I have fought against Rhino (easy), Klaw (fun) and Ultron (challenging) so far, and I look forward to see how every scenario and villain will twist the game rules in their favor. (Ultron, for example, really seems to be easier to defeat with heroes that prefer to stay in alter-ego form, and therefore was quite a struggle for the way I built Kitty Pride/Shadowcat, who stays in hero form for most of the duration of a match)
Would absolutely recommend anyone looking for a replacement for Legendary, who loves Living Card Games and the challenge of building optimized decks.