I'm really digging the art but if it's truly a real rip off, I think they'd use the same art/characters. Looks like they only took some of the art styles and the mechanics. However Japan won't give us the game so these guys gave it to us. Reminds me of people that make those Pokemon-esque games because Nintendo is never going to put Pokemon on the app store. I really don't see the problem unless the game is broken in some way to steal your money.
The only part that really turns me off is needing the internet to play when you don't really need it (except for the friend mechanic). With an ipod touch, this is pretty hard for me to play.