I bought a used GPT8005A about three years ago, and it works great. There are afew times that the tracking seems to get confused, especially when there is alot of glare behind you, but generally a quick reset will generally fix the problem. I use teh Satel radios, and they seem to be bullet proof.
I would not hesitate to purchase one again. I have used the Trimble 5603 and the Leica SmartStation 1200, and this one is my favorite, believe it or not.