I started getting wear on the buttons of my 62s on about the second day of use...in comparison my (at the time) 4-year-old 60CSx, treated in exactly the same way, showed no sign of button wear at all. I told Garmin about this immediately I returned from my first real trip (2 November 2010) and kept them up to date on the progress of the wear (with photos) over the next few months, so if they are STILL saying several months later that this is "not a known problem" then they are lying.
Another major problem I've had with the unit is freezing up - usually at least once on a trip of 2-4 days, with the maximum (immediately after following Garmin support's instructions to upgrade to the latest firmware) being 3 times in one day. I've sent them the tracks, but so far they seem unable to sort the problem out.
Then there is the insistence of my unit on splitting tracks into 3000-point segments, with only the last segment of the day running over this limit and up to near 10000 points (it is supposed to split into 10000-point segments). Again, Garmin have not been able to provide a solution and no number of firmware updates have sorted this out.
Perhaps most frustrating of all though, are the things that Garmin don't even perceive to BE problems - the utterly bizarre GPX file naming format that makes it impossible to sort tracks by date (yes, I know they will tell you to sort by modified date instead of name, but try this after splicing multiple tracks from one day together!), and the equally dumb waypoint naming (using 12-hour instead of 24-hour time) that means tediously doing manual conversions of date & time of waypoints imported into Excel. To be fair to the 62s, this is something they have sneaked into the 60Csx as well during a firmware update a year or so ago, so I have the same problem there now as well, wheras in the past it was easy to convert waypoints into Excel-compatible format!
All in all, I am highly disappointed in my 62s, I always have to take the 60CSx along as a backup in case it freezes and I lose track data, and the only feature it has that I like (even though it has serious limits) is the custom map capabilities.