I used it for about a year. I used it on my 10" ASUS tablet with internal GPS antennae, no cell tower coverage. It was cheap for around $50/yr. with updates. GPS is a wonderful thing to have. Two things... 1). I fly a spam can. External antennae probably would have made it work better in the 172. Lots of guys at my field use Naviator on a tablet in Champs, J5, Piper short wings, and Chiefs. They don't seem to have the issue with the loss of GPS reception that I sometimes had. I believe they all use just internal antennaes. I think you might have the same outages in your machine because of the Al wing without an external antennae. 2). The screen is really hard to see in bright sunlight. At night, no problems seeing and GPS didn't cut out as often. Naviator worked great, it was the hardware and the user that caused me to let my subscription lapse. I found when I used it flying VFR, I was looking at the screen and fiddling with the gadgetry more than looking out of the airplane. It's quite unnerving if you are flying somewhere new, monkeying with the GPS, not paying close attention to landmarks, sectional chart, and the damn thing blips out. Take it for what it's worth though, my kids and wife lovingly call me their computer cripple. They are convinced the wheel is still new technology for me.
Jim
Jim