Ditto on what AKFireMedic said.

A UCD 60 with a ST 90 was my first "real" 3D plane. The UCD 60 works great for hovering, torque rolling, harrier rolling, blenders, KE spins, and inverted flat spins. But in harrier flight it pretty much sucks due to severe wing rocking tendencies, and knife edge has serious pitch and roll coupling. Since harriers and knife edge are some of the fundamental 3D manuevers, the UCD 60 is a handicapped 3D plane right from the start.

I still have my old UCD 60, but it's pretty much been gathering dust since discovering how much better profiles are at 3D flying. Once you've flown a Mojo 60 or a Katana 70, the appeal of a UCD 60 quickly fades away.