I bought one of these units in Canada at the start of 2006 when they first came out. I've used it extensively in the last year as I work as an geologist and have logged over 10,000 km of tracks in N America plus Europe but mostly in Mongolia where I consider my GPS to be 'mission critical'. I've been using GPS units since 1993 and have gone through Garmin 12XL, 12CX, 48, etrex, 176c, 176, and 76 units.
The functionality, ability to customise the screens, the usually good (see below) lock onto satellites, the accuracy, the ability to record a 10,000 point tracklog at 100m resolution, and the ability to log the track to the SD card as you go along are winning points. The last point is the reason I bought this unit - if the unit breaks 6 days into a 7 day trip I can still recover all my tracklog from the SD card.
But I've had 2 apparent software issues with this unit. Originally the unit would randomly turn off if kept on the altitude screen - this was fixed after a software update downloaded from Garmin's website. I now reguarly check their website for software and firmware updates (make sure you install both). However, now the unit sometimes has a problem where it cannot hold a lock on to satellites at speed and has to re-acquire the fix every second. This means when driving you loose your speed and direction information, get a break in the tracklog on the GPS screen and when you download the track to a computer you have to join up 100's of individual track sections from the active log, all recorded at a few second intervals apart (thankfully this is easy to do with the latest version of Garmin's Mapsource software).
The unit gets 3 stars. It would have got 5 except for the unit's software issues, Garmin's international support (Garmin only accepts units for repair in the region that they were originally purchased in) and the high cost.