Yes, I've flown it a number of times Gary. Great little unit for the price. You've actually seen it fly in my 7.5" Little John a number of times and didn't even know it, lol! I have it mounted on a sled I can move between nosecones. It uses a max-6 ublox chipset, and helical GPS antenna which has much better coverage than the ceramic patch antennas many others use. The radio range is supposed to be 5-6 miles, but I have not tested it beyond 2 miles up, and ~1 mile on the ground; has not been a problem.
On my flights, it sometimes looses GPS lock on the way up, but reacquires well before it lands. I have not looked carefully at all my flights to see if it always looses lock on the way up. I think though this is typical for GPS units.
The main issue is that for only $300, you have to hook the receiver to a laptop to collect data. The supplied software is just the demo program from ublox, and while it works fine, it can require hunting through the log if you don't copy the coords before you stop the logger (sometimes don't have contact when on the ground if the rocket drops behind something a ways away). This is one more thing you have to do for a flight; some other GPS's out there have handheld receivers which is simpler, but cost more. Someday in my non-existant spare time I plan to write some better software, more tuned for rocket use to make it a bit easier.
It also does not come with a battery, or battery holder. 9V's are OK, but I've been using 7.4V lipos that for similar weight, give longer run times, but require specialized chargers.
