I'm with Marvin!

I've gone over 1600ft once or twice in my Hotspot but it was a real challenge and boy did the plane ever get small. Here's a chart from a couple years ago, breaking 1200ft 2x. Its interesting to get a feel for verticals like this, knowing what your airspeed was prior to turning it around. It gives you a whole new feel for the performance of your jet.

I've tried the GPS expander (the older one) and found it tended to straight line a lot of the corners if you were too fast. it might have also had trouble tracking satellites, since we were somewhat shielded in a valley. The images below are from different flights.

Excellent system in my opinion.

Kelly