RE: 60 size trainer, or Avistar
I second fearlessJOE's comment on the Arrow. Have one and until I flew it into a tree, it was the most fun I've had with r/c to date. It's tough, flys well (although you'll want to ditch the three-blade prop it comes with), and it still slows down and lands like a trainer. I'm extremely comfortable flying beginner acro with it and recommend it to anyone (plus the price ain't bad). You may want to put a .46 or .50 in it to gove it a bit more oomph. I've been flying mine with an OS .40LA and it's not bad, but I think a little more power would make this thing rock! I'm going to probably buy another before I get into a low wing like a Four Star 60 or similar.
Good luck whatever you decide!