I have been flying the wings off of a Ultrafly Outrage electric biplane lately. Not at all difficult to fly but not a beginner's plane nontheless, but then niether is an aerobatic monoplane. I did take a little while to get used to orintation with those two wings and it needs a little power to do a nice landing.

I have always liked biplanes. Back in the days when I flew control line planes, one of my favorites was an .049 powered profile biplane. One of the most awsome airshow routines I ever witnessed was done by a full scale Pitts Special.

It's not that they are especially hard to fly so much that there are no biplane trainers on the market. If you can fly a low wing sport plane, you can fly a bipe.