I learned 3D on a mojo. I had planes marketed as "3D" before that but they weren't. The UCD will teach you how to hover or flat spin, but they are eggshell fragile and don't do the high alpha rolling maneuvers well and have lots of knife edge coupling. A mojo does everything well, and is near unbreakable. I have a Primo and just did a forward flip into the ground at full throttle (not too smart I know, stupid wind..) and only crunched the rudder. Thin CA and some new covering and it was good as new. Would've been a total loss or at least a broken fuse behind the wing on a UCanDo.

Mike