I had a Saito 1.00 in mine, Once the motor was run in and tuned properly, it was OK. Not unlimited vertical but still fun. I then put a Saito 1.25 in it to run in the 1.25 - Man what a difference that made. I am running an APC 17x4w on it at the moment.

The G90 should have enough power, was it tuned properly and what prop did you have. The U-Can-Do is a plane that is not meant to be flown fast so a finer pitch / larger diameter prop is the way to go on it.

If you go to the Saito 1.00, try a 16 x 4 Prop. I had a 15 x 6 on mine when I tried it and I think that the finer pitch would have been much better.