Arcana Heart 3 is one of the most solid, in-depth and balanced fighters you may ever play, if you have no problem with its...."aesthetics". (And given how you already admit to loving Touhou? Some how, I don't think that will be a problem...)
Any way, what probably impresses me more is that this another of them Doujin fighters that ACTUALLY tries to do more along the lines of its own thing, and not just be yet another one citing from the book that Guilty Gear and Melty Blood wrote practically a decade ago. No air-dashing in sight, which actually means going back to more ground-focused combat, instead of IADs being a part of the range game.
So far, I'm impressed. Ideally, this could be a whole new player to the field that sets a new standard for Doujin fighting games, like how Melty Blood did so almost a decade ago. And like MB, I'm hoping that this game becomes a Dark Horse that can eventually be playing with "the big boys" in the arcades.