My experiences are limited to
Tracker Maxima 5000/50 - compact, limited range, had a tendency to 180, not real precise, but I never lost a dog with it. I never used it with a Yagi antenna, I think that would have helped with accuracy.
QuickTrack 6000 - easy to use,so easy that my 8 year old daughter likes to track the dogs with it. A little bulky, I would not like to carry it all the time walking through the woods. It will 180 with the quick shot antenna, but not as bad as the Tracker. Much more precise than the Tracker, at least in my hands.
Garmin w/ DC30 - Really neat, however I tend to watch the screen on the GPS more than the dogs. I don't trust it enough to run solo without radio collars. The batteries have to be charged often (not the case with radio), longevity/ collar life is questionable. It will get me to a bay quicker than with a radio system.
That's my two cents....
If I had limited funds to spend on a system, I would buy the Garmin system, then pick up a couple of used radio collars. That way if the Garmin fails, you can always call a friend with a radio system to come find your dogs. You might not like the razzing you get, but at least your dogs will be back
