Japan seems to have quite a large number of belt drive airplanes and options compared to the rest of the world. I have no idea why.
To be honest, I simply wanted to try the belt drive. I saw a Youtube video of the Fantasista 70 with the unit and saw pictures of the unit. I was just fascinated, same way I was when I first saw a Brenner Contra.
The Fantasista 120 is my favorite plane, so I am sure the smaller version will not disappoint.
You can run a larger prop using a smaller motor and from what I can tell, it does sound a bit different in the Youtube video. I'll know more in the spring!