I have considerable experience with the Zero Gravity. It requires a lot of patience to get to fly decent. Lots of mixes required. Once I got them figured out the it has been a decent little plane. In no way does it compare to the PA Extra or Katana or the Sebarts in the same size range. It is more of a novelty. Having said that I know some really good fliers that felt the Zero gravity just was not worth the time and effort. It is built beautifully well, however. Having said all this I will say that I have always found 3D bipes to require considerable work to get to fly decently. I have no experience with the PA ultimate. I do enjoy the zero gravity though now and its a real fun fly.

bob