I don't have one, but most reports say its very underpowered at 7.2V. All-up weight appears to be critical to flight performance, so you might try Li-Poly batteries.
Most reports that I've seen who were happy with it had 8 or 9 cells. heat-sinks on the motors, and frequently lubricated the shaft.
GWS is planning to release an updated kit with larger motors, but hasn't given a release date.
Here are some tips:
http://www.rcuniverse.com/showthread...=&goto=newpost]