I am not a gunwriter, but I have one (a Garmin dog-tracker, not a gunwriter!) - works fine with my setter in (MI) Upper Peninsula aspen stands. Also have a Tritronics e-collar and beeper on her on a seperate collar for control / continual location; this does require use of 2 handheld controllers. I think I have on occasion had some interference between the 2 so I now just check that the Garmin is trackign before we start hunting.
FYI: Garmin has purchased Tritronics. Available as of this fall is an e-collar and GPS tracker that use only one handheld control unit. I think the combo is around $700-$800. (Lion Country Supply has these in addition to the unit you linked to.) The combo handheld unit will NOT turn the tritronics beeper on and off, you have to it manually.
The tracking unit you link is the older (NOT obsolete), pre-purchase of Tritronics one (which I have). If you're just looking for a tracking unit, that would likely work fine. Some folks (including me!) have not found the compass / tracking map in those units to be the most user-friendy since they have to be held level to the ground to use (supposedly the newer units do not - I have never tried one).
Regarding the combo unit, most of the birdhunting site reviews I've looked at have been positive.
My personal strategy is going to be to use my current equipment a couple more years in the hopes they build lighter, more user-friendly stuff once they gain some experience with combined GPS/e-collar systems.
Last edited by ralphbeagle; 11/28/12.