I have dealt with both the superstar and avistar's clamp motor mount. It's fine, but I recommend you swap out the phillips head screws for some hex head screws. I stripped the heads on the phillips in no time. One nice thing about this mount is the ability to adjust the CG somewhat by moving the engine forward or backwards.

B.t.w, I cannot say enough good things about the Avistar. I put about 35 flights on my over the weekend, and never bored of it. I liked it much better than the superstar that preceeded it!