I've got 130 hours in this game. One of my favorite of the year.
They've created some of the best versions of multiple classes that I've ever seen. The moment to moment gameplay for 2 of the healers, 4 of the tanks, and multiple damage dealers are pretty much the best versions of that kind of class I've ever played. Vigilant, one of my favorite snipers ever. Roadblock, one of my favorite tanks ever. Murasame, one of the only actually good DD tanks I've ever played. Nimbus, extremely original and interesting gameplay for a healer. Skywave, flying healer that plays 100% different than anything else in the game. The list goes on and on.
If they manage to make this game an acceptable success, it would 100% rival Monster Hunter as an ongoing series. They have a few 10 person co-op events that are fantastic.