I've owned both the Edge and Extra from 3DHS, and now the Crack Yak and Extra Slick from Twisted, and have flown everything they make in that size. I fly for Twisted now so take what I say with a grain of salt
Anyway, any of the 32-35" airplanes from either company would make a fine 3D trainer. They are all very durable and fly very well, but I prefer the airplanes from Twisted myself. The foam is stiffer and the planes fly more precisely, and the planes go together quicker.
The Extra Slick flies most like a wood airplane out of all of the airplanes that Twisted offers. The Crack Yak is faster, more responsive, more capable, and more rewarding to a skilled pilot (but it's by no means hard to fly). The Edge and Sbach are more sedate and a good introduction to 3D aerobatics.