Went ahead and jumped right in, and so far it's worked fine right out of the box. Although I have a few issues with it (as some have already pointed out):
-The whole 57-59 framerate issue. I turned on Steam's FPS counter, and I see it too (although I haven't run into any sync issues, and it's still smooth).
-The soundtrack for version 1.5 being low quality compared to everything else.
-Not going into fullscreen even though I tell it to (but it saves the other settings I had it set to with input and scoring). It does go into fullscreen when launching just fine, but it feels completely random.
-Not saving the high scores when I exit out of a game mode and go back into it.
I guess I'm really lucky that I haven't experienced a crash at all, and trying to Alt+Tab it didn't crash the game. As far as the game goes, I'm in love with it (then again I loved Mushihimesama Futari on the 360). Hopefully these issues get ironed out, but for the most part I'm okay with it.