I bought a "Nuvi 550" some month ago and it's ok for car-navigation and most "standard" geocaches (traditionals & multis).
But for "Wherigo" it isn't usable at all:
In the last few days I tried 2 cardridges in my "homezone" (which work fine in the version for PocketPC-Users on these devices).
The first one
http://www.Wherigo.com/cartridge/details.a...f8-8be958e12251
allways crashes already during start (the nuvi 550 needs a hard-reset to get re-animated).
The second one
http://www.Wherigo.com/cartridge/details.a...5f-212244e3b12d
constantly crashes at station 2.
Even the garmin-demo-cardridge which was on the nuvi 550 by default (the one with the spaceship) hardly crashes near the end (while refueling the spaceship).
So garmin and/or Groundspeak did a very bad job on creating a stable Wherigo platform - especially on this device. It's a shame...
Greetz to all