My Garmin 62stc had the power button fail after 15 months of use -- purely mechanical, it just started requiring harder and harder presses to turn on the unit. I could still communicate with the unit via the USB connection.
I've known several other people who have had the same issue with recent garmin units; this just seems to be a problem of poor manufacturing and quality control.
In any case, I sent the unit in for replacement by a refurb ($110 plus shipping). While waiting for the new unit to come back, I talked with several people who had bad experiences with Garmin refurbs.
When I got the refurb unit and turned it on, it immediately came up with "cannot unlock maps." I called garmin, and they said this was a common problem with stc units, they forget to unlock the 100k maps that are supposed to come with a 62stc, or just corrupt the unlock code. WTF? Don't they do the minimal, most basic checking of the unit -- e.g. making sure it turns on without errors, before sending it out? It doesn't take a genius to know there is something wrong with a unit when it displays an error message immediately upon power-up.
I've collected perhaps 5 stories from people who had serious problems with their refurb units. Is this a remarkable coincidence, or has Garmin added unspeakably bad QA/QC to their reputation for unspeakably bad manuals?