If you`ve flown a high wing trainer with a flat bottomed wing, a logical move would be to something ( high or low wing ) with a semi-symetrical wing. If you want to stay with something that you might be familiar with ( high wing ) yet offers better performance, IMHO it`s hard to beat an Avistar. With a good 46 up front it`s an excellent basic aerobatic airplane and a bit more demanding, though not greatly. Hear good things about the Midwest Aerobat as well.