I have two, functionally they both work pretty well. I have trouble getting the elevation and barometric pressure to match the readings broadcast from a local airport. Probable user error on my part. The electronic compass works ok for general directions but I would not attempt to navigate with it. I use the DA and wind velocity function and on both of them a lot and it seems to work well. However one unit Eats batteries, it will run a $7 battery down in a week and the battery in the other one has lasted 6 months, go figure. I think they are pretty good value for the money.