I downloaded the Open Beta today and started playing it a bit. It's pretty good, better than I thought. Graphics are good and the inclusion of all the demons is cool as a SMT fan.
My gripes so far are the HUD/UI but that goes for pretty much all MMO's for me, I think they are terribly dated and unintuitive and SMT:I doesn't change that. Also the character movement speed is almost excruciatingly slow, and I'm not sure if I can speed it up or not.
Anyway, anyone else here playing it? Teaming up would most likely make the grind easier and more fun.

The link for the download is here: http://megaten.aeriagames.com/download
It's a little over 1Gb and its free-to-play which is a huge plus.