Yes, when my computer radio needed service, I was toast for a bit, had to fly my plain jane radio and limited myself to one plane to avoid the hassles of re-setting other models. But when I think about how many students mess up the trims from one weekend to the next and all the time wasted trimming both the master/slave, at times having to call a more experienced pilot to trim out the buddy box, well I wish more students came by with a 9c. Sure its only a bit more extra time, but when you have 5-6 students and only you around, every little bit helps. All you have to do is neutral the buddy box trims, and make sure that all the surfaces are going the right direction. It also allows easy buddy boxing with a heli, all the mixes can carry over.

I do always have the student set everything mechanically, besides there aren't a whole lot of things one can program on a trainer with four servos. Oh yes, another thing I like is having a timer built in and tied to the throttle.