Well i have been looking at getting one since this type of unit first came out overseas. Then Garmin introduced the Astro in the US. WItht he new improved collars I decided it was time to get one when this years tax money came in. Talking to a partner about it he could not wait for me to review it. He had to have it now. It arived, and I had to set it up , and of course got to test it. Below is my first expeiene with it. Pulling the unit and collar out of the box I iked the overall looks. Both units looked very sturdy and well built. GPS-I was really impressed by how fast it aquired position. Even while standing in my house had no problem. My old Lowrance would still be looking for a signal. Overall use is very simple. Never opened the user manual once. There are a bunch of options for having 8 buttons,but a little playing and you will work it out fine. I don't care for the double A battery use, as a battery pack would be nicer. Which would allow a truck charger then hopefully. Collar- looks great, charged fast, and pretty straight forward. have heard complaints about battery life. This comes from hound hunters using old standard collars with up to 17000 hours. These collars will last over 30 hrs before charging when set to a 30sec refresh rate. Been along time since I hunted that long. So charging them up should be no big deal. Software- This is an option that should be gotten. The Topo USA 2008 should great detail, and was easy to use. In testing the unit from home. I sent my daughter out with a collar in the truck. I tracked it for 1.53 miles before losing it. Then got to use it in the field the next day. Here I only got out 1.2 miles before I seen I needed to get to the dogs for safety reasons. While I was tracking at this point was comparing it ot my Tracker maxima unit. Just before heading to the dogs I had lost signal on one of the dogs on a tradtional tracking collar, and the other was just about maxed out. So with the old stuff I lost one dog, and knew the direction one was but that was it. With the Astro I knew exactly where they were. That coyote chase ended being in a dangerous area. Luck was with us, and we found another set of fresh tracks only 30yds from my truck. VERY NICE!! So the dogs went back out. Never got real far from the dogs. About 1.29 miles. It was nice to watch the race and see exactly where the dogs were going. Suprised the yote and dogs by showing up in places they have never crossed before. On this chase they headed for a highway crossing. So I went to that crossing. Sure enough the yote had already been there. But, wait they were on a pair. As I watched the gps the dog kept coming to the road up from where I was. Figured the dog was coming and the map was off. So I waited. The dog was in the road on the gps, and so was I. The dog however was 400yds away on the gps. Well since it was niot where I was I went to where the gps was. Sure enough ther is the dog and the yote track. he pair had split. Got the dog across while the other came on the other yote back 400yds away. So I got there and got it caught up, and back n with the other dog. This chase continued and got to wathc and play cat and mouse with the GPS the rest of the day. Was neat to see how far the dogs had traveled and at what speed. On this chase the dogs had gone 18.73 with an aveage speed of 3.53mph. Did lose signnal a few times around a mile, but got it back. Still even If I could not find it I knew where the dogs last were to egin looking. Well mypartner picked his unit up that night. We hunted the next day togehter so got to wathc it again, and show him how to use it. While we were checking tracks left a collar on at the truck. We tracked the thing out to 3.2 miles. Once we got the dogs on it never got that far from them. Overall there is no doubt I wil be buying one very soon. I find the problem with them to be is we know too much. HUH< what does that mean. Well, it's simple. The gps tells us exactly the range we are getting. With the old style tracking units it was always a best guess. Sometimes you may get good range other day not as much. Even on the best tracking days it was still a best guess as to where the dogs were. Bounced signals were worse on the best days so you went in oppiste directions. Never really knew exatly where the dogs were going. Now you can exactly , and get there. There are some things to think about when it come to range. The collar talks to the gps unit via a digital vhf signal with 2watts in the murs band. hat is 151, 152,154. So realistically you can expect the range you would get out of a handheld marine radio. Just like any other type of communication device atmoshperic conditions, weather , etc will affect the range. Don't forget about the selective availabilty put in by the military. Overall the SA will not affect you in finding the dog treed or otherwise. It does play a bigger rle when trying to find a 30ft hump in a 300acre lake when you are off by 200ft. Range can be extended with the use of external anntennas. This increases the line of site, which is how all radios work. So the truck mounted radio is a must buy. They have also come out with a handheld antenna. This attaces by a cord to the unit and you hold the antenna in the air. I will be looking for a telescopic model as well. Not offered by garmin yet, but maybe the ham world will have something. I have heard of guys getting range out to 12 miles in the mountain areas. Think about it in that respect. You are up high increasing line of sight. The foilage of the sumer may affect the units like anything else. Still these units are far better than the GPS of 5yrs ago. Like I said above my old Lowarnace is still trying to find me in the house. I will be buying the unit, and testing it more. Also a few old guys that I hunt with will have them. Seeing how they have trouble with tv remotes. I will know them in and out shortly. I for one will own and put the trust of my best friends in them. Please if you have any questions feel free to contact me.