I'm using a GPS II and it's been working ok. The hardest part is not having any street info as it's not a mapping unit. I beleive the GPS III is the same. I have had my unit for about 10 years with no problems. I take that back, just a couple of months ago the rubber seal for the data port finally broke
Over the years the unit has been dropped, gotten wet, etc and keeps going. But the need for street info is getting to great and now with the seal broken, it’s about time for me to upgrade.
Chris