Well, I'm winding down the grouse season up here in SE Manitoba Canada (1 week left) and I definitely have some opinions on my Astro.
First off let me say in principal I absolutely love the thing, and I think it will continue to change the way I hunt and train, and is a major stress reliever for me.
I'm in heavy cover a big bunch of the time and can report that range is at least 923 yards (that's where he figgered out he was going the wrong way on the trail). That's the farthest anybody went with it, and I haven't got around to sending Mom out in the pickup to see what the maximum is for sure.
I love the map feature. It's great knowing just what an individual dog is doing, how fast he is going, how far he went etc.
Being a belt and suspenders guy, I still have the beeper on the dog, so I don't have to look at the GPS all the time (unless I want to). The beeper seems to signal point faster than the GPS, and I can hear my beeper 200 to 300 yards under ideal conditions.
Actually the Astro may have saved my dog's life already, so I have no complaints about the money spent. Two weeks ago I was hunting near the NW Ontario border in heavy boreal forest. Birds were abundant, and it seemed we were getting a bird contact every 10 minutes or so (ruffs and spruce grouse). My dog had just pointed a double and things went well for a change, and was pretty cranked up when he completed the second retrieve.
I lost track of him for several minutes, couldn't hear the beeper, then heard the point alarm go off on the Astro. He was a little over 300 yards down to my right in a cedar swamp. Lovely.
I started down briskly, not expecting the bird to still be there when I waded through the jungle.
Suddenly my blood froze when I heard a timber wolf howl right where I thought my dog was, followed immediately be a couple of other wolf howls also nearby.
Then I heard a wolf yapping, and my dog bark back at him. I realized my dog wasn't pointing, but was standing off a pack of wolves that were rapidly surrounding him.
Now these aren't your little 35 lb coyotes. These babies might run 120, and could probably look in the windows of your SUV without picking their front feet off the ground.
I was about 80 yards away now, and fired my 12 auto in the air a couple of times and started yelling, while wondering how #6 shot would do against one of these monsters.
Fortunately, I never got to find out as my ruckus must have worked, and my dog appeared, tail between his legs, and a nervous look to his eyes and ears.
Now, on the negative side.....
The factory antenna is WAY too soft, and has a hard plastic base inside. It's fine for open country, but a hard driving dog in heavy cover will just rip them off. I would put about 50 wraps of electrician's tape around the first 3" to stiffen it up and prevent it snapping off at the base. I have the new stubby antenna on order, and I've been waiting a couple of weeks, but it hasn't arrived yet.
The plastic retainer for putting the dog unit on a collar lasted only a couple of weeks, before it was shattered as well. Again a hard plastic was used. It should be nylon or something more durable. I haven't ordered a new one yet.
I've been using the vest the last month or so. Again this is an open country unit. It seems that the tab that goes around the dog's regular collar can get ripped off if the dog strikes something hard enough, and then the dog will just run out of the vest. It has happened to me about 4 times so far. Twice the dog stopped when the vest tangled his back legs and he waited for me to fix him up, but a couple times it came right off, and then you're praying you can spot the unit in the snow and cover.
I may just stitch that tab closed at an appropriate overlap and thread the collar through it every time I put it on. If that fails I might design a whole new harness, perhaps out of an old nylon roading harness, and attach it with buckles.
Now in all fairness I must admit I'm grouse hunting under the heaviest possible conditions with horseback shooting dog pointers, none of whom would consider slowing down at all in the thick stuff. Gotta be pretty close to the ultimate durability test.