It seems with less geocache waypoints, the responsiveness picks up. It looks like it just has trouble calculating the distances with that many points. I went from 190 to 100 and the speed was better. Still not acceptable, but better. I wonder what the optimal is? If the geocaches could be loaded as multiple files that would be better.
I'm off to return my Triton 300 for the Explorist 210. While I lose colour and a bit better geocache listings, at least it is more responsive.