I've got a Garmin III - it's a brilliant thing.
We took 5 aircraft all the way to Dakar last June (3 DR400, 2 HR100). We all hade the GIII in the planes, all the way points, VORs, airfield info we needed were there.
No problems whatsoever. It would have been real freacky to navigate in the Mauritanian desert without them (to Atar and back).
On top of it all, it's small enough that you don't just get glued to the thing.