I love my Avistar....still have it and still fly it. I powered it with a Super Tiger 45 using an 11=6 MAS prop. I get unlimited verticle. Its easy to fly....and can do quite alot with out a ton of effort for a trainer. A worth while upgrade is installing a dural style main landing gear.
Ive thought of selling it to fund a pattern/3D plane...but havent gotten myself to do it yet. Its my laid back aerobatic plane when I want something simple.