Anyone else clicking on goons for loot?
For those that aren't, Marvel Heroes is a free to play Diablo-em-up set in (as you have no doubt cunningly surmised from the title) the Marvel universe. It's similar in aspect to the old X-Men Legends/Marvel Ultimate Alliance games, you choose a marvel hero and go out and punch bad guys until loot falls out of them.
The core experience is pretty satisfying, the design favours large numbers of enemies and frequent loot drops, and the loot is reasonably interesting, with higher rarities having more varied effects than just +numbers (boosts to skills, and unique on-hit effects).
It uses physics for enemies as well rather than canned animations, so big hitters can send enemies flying in an entertaining fashion.
It's all multiplayer, and most zones are public, which means there are large numbers of heroes running around, but since enemies spawn frequently and there are area events and event bosses that are designed for everyone to gang up and do (so eg. Venom will appear and everyone goes to bash him) you never feel like you're not getting any action. Also loot is individual, you can only see your own loot drop out of bosses, so there's no loot ninja business. (Plenty of the other kind of ninjas. The kind you punch).
Boss zones are individual though, you enter them, fight through an instance, fight a boss. By the end you'll have punched most of the people who really deserve punching in Marvel.
Obviously, being free to play it's worth looking at the business model. You start the game by choosing a hero from a lineup of 10 or so (It was only 5 when I started, there are currently 27 total and they keep adding more, about one a month or so), and that's your first character. You can get other characters by either buying them with real money (and the prices basically vary by popularity. Expect to pay significantly more for Deadpool than billy-no-mates Cyclops, for instance. That's possibly the worst part of it, the popularity pricing is quite cynical, even if the prices aren't mega expensive given how much playtime you can get from a single character), or you can gather an ingame currency which can be traded for specific heroes or a random one. Going random is cheaper but might give you one you already have (in which case it powers up their ultimate power).
There's also the usual raft of cosmetics to pay for, and paying for stash space and boosts to XP, item drop, etc.
It doesn't feel like there's any ability to buy power, even though some characters are definitively stronger than others it's still quite possible to play through all the content with any of the characters, and you can get all the characters for free, and PvP is limited to duelling in one specific area and that's only just been introduced.
If anyone is playing, who are your toons? I currently have Thing and Squirrel Girl (because who wouldn't want to play as Squirrel Girl?).