I bought it on day one, it's good (but that's subjective). I got around 180 hours out of it before I stopped. I reached "end-game", stayed there for around 20 hours of play or so, and eventually had my fill. All in all I absolutely do not regret the purchase. And I love the game's soundtrack, very memorable. The combat system is great, physics-based and dynamic, and the Large Monsters offer a good variety of different fight patterns for you to memorize. There's a good selection of weapons to choose from (and all of them can be used, there's no "Class" system; the weapons themselves will determine how you play the game, how you gear up and how you build your character, around said weapon of choice).
You should go check the Recent user reviews on the game's Steam page as well, there's plenty of reviews there.
As for keyboard and mouse support it doesn't "suck", at least not for me. The one thing I didn't like (but still tolerated it) was the initial Mouse sensitivity and movement 'feel', it was weird. But that was fixed one or two patches back (when rotating the camera with the Mouse originally it moved as if it was a gamepad joystick; it felt pretty bad, but it's gone now). That mouse sensitivity setting I believe now can simply be changed in the options (I do think I did have to do that). You can do some decent key bindings for quick actions (Potions, Consumables, Taunts, Communications to players, etc) as well. I mean it's functional, I didn't have any problem with keyboard and mouse (well other than the initial weird Mouse sensitivity but that's about it).
For me, at the moment, still have my fill. I'll go back to the game eventually when all the remaining Large Monsters have finally been added (the PC version of the game is still missing something like 3 of them by now I think). The gist is that the game isn't a typical Never-Ending MMORPG with large updates every 3 months where you just keep on playing and never find an end to it. In this game you do get to "end-game" (Slaying the Elder Dragons essentially), but once you 'Maxed out' your specific build and gear, and once you finally Augmented your preferred weapons... you're basically finally done with the game in terms of actual progress. If you keep on going after that it's only because you want to repeat the process with new weapons that you didn't try before, but that's it; there's really nothing else after that. But that's ok, I do not mind when a game... you know, when a game has an ending. Not everything has to be an MMO.
So yeah, no regrets for me, had a blast with it; good fun with people too (can be played with up to 3 other players) and I'll keep listening to the soundtrack outside of the game regularly, it's just awesome.