Both the 40 and 60 size are a lot of fun and great flying planes, but to me the 60 size just feels "lighter" in the air. It's much lighter for it's size than the 40 (i.e. lighter wing loading), it seems to stall much slower, and "crow" mixing seems more effective too. A Saito 100 is perfect - hovers/TR's at about 1/3 to 1/2 throttle and pulls out vertically with authority.

Either way, you'll really enjoy an UltraStick!