twin towers level is the best out of both apps!
It's great for just tooling about in acro mode, but I have noticed that in timed trial that from one direction the "stars" are invisible except for the light they cast.... (sometimes if you miss, you might have to do a check point from the other direction...)
I just wish you could take that terrain, and place different trees, gates and other models ( you'd only have to allow them moving on the lanscape with the height set to the ground level at that point)
the ability to spit the "level" out as xml would be fairly trivial - done it in a few apps myself - this would allow community sharing of race tracks....