Hi Davcos, I think the most challenging plane I ever flew was a great plane VENUS 40 - This thing was very touchy no matter where you put the CG. It woke me up whenever I flew it (snapped all the time - but made it fun). Finally sold her and baught a GP extra 300. I will have it built probably buy july. My other plane are a GP U-CAN-DO 60 and 46 size, also a couple of eflite electrics - nothing to brag about - Steve