Bill, I agree with Roger 100%. Any GPS is a machine and machines can fail and, according to Murphy's Law, your GPS will only fail when you are lost :-(
However, I have a GPS and love it! I really like the idea of researching a trip and uploading it to the GPS before I go and, I like the idea of downloading the trip after I return, especially if I've taken a really cool detour! The GPS allows me to keep a computerized record of my past and future trips. Also, upon my return, I load my trips into Google Earth Plus so I can see it in 3D and even do a fly-thru!
I guess this type of thing may not appeal to all but it will certainly satisfy any geek streak that one may have!
If you get a GPS, my main recommendation is that you get one with the high sensitivity chip. I think it's called SIRF III or something like that. Mine will track me through a cave (don't ask me how) whereas my old unit would loose me under the trees!
I have the Garmin MAP 60CSx which has all the map functions and will direct you turn by turn like a car GPS. I weighs a heavy 7.3 oz. All this is unnecessary for hiking and gets to be very expensive by the time one adds all the maps but, like I said, "It's cool!"