For those of you that use them, how accurate (how many feet) are these collars? I assume that they have the tracking/shock combinations?

I can track my dog about 5 miles around my area we have went a lil further on flat land ...I think says there accurate to 5 foot
The Garmin alpha 100 has a track and train function. That will shock also

I know mine is very accurate. 5ft or less. What I notice is a slight time delay back to the handheld unit.

Mine are pretty accurate but I don’t have the shock option. I wouldn’t shock a dog I couldn’t see.

In settings you can change the refresh rate, but your right occasionally it'll "hang up"

I've found them to be pretty accurate most of the time. I do like the ones with train mode so you can at least tone them and if they don't you can shock them. Some dogs respond differently to them. For instance one dog you can tone to stop them and holler them out to you, the next dog might stop and not move till you go in and get them. I think this happens when people turn the electricity up to much to begin with.

I’m not looking at it for a dog application, just the accuracy and functionality of the unit. If it’s GPS based, I’m sure for the right cost, someone can make it as accurate as a foot or so right?

I agree they are accurate within a few feet.

Plenty accurate enough for intended purpose. often I will be standing right next to collars or even have them in my hand and it will show 15-20 feet away.

The Garmin Alpha is top the line paired with a TT15 collar you can track and train the TT15 also has a vibrate function. They are pretty accurate however heavy overhead cover can cause loss of GPS signal, although Ive only had that happen 1 or 2 times while tracking. Also the range on these collars are tested in wide open areas out west where there are little to no trees per a Garmin rep. However they are pretty close when it comes to actual location. Like someone said the refresh rates can be adjusted, and keep in mind they are like any other GPS system as updates occur you must update your collar and handheld with Garmin.