Spacey, a lot of Chippys are locked away inside their owner's hangars ! From what is available the Chippy would be close to the top of the list.
Any trainer with aerobatic capability and a tailwheel produces a thinking pilot. Maybe all the Chippy needs is a big radial in the front (ok for Chippy maybe a small radial..)
The Tomahawk I think is the best of the nose wheel trainers, because it teaches the student to look for individual characteristics in aircraft - the Tomahawk has plenty that stand out, some quite bizarre/hilarious. (I had to ferry one and I was hooked !)
Maybe the unpredictable spin characteristcs are seen too much in terms of risk of non recovery - which comes back to spin training or lack thereof. The problem may well be what the pilot knows, or does not, and not what the aircraft does.
[This message has been edited by Vx (edited 10 March 2000).]