I bought this to work with torque, an android application that displays all sorts of engine data. The application itself is well supported and I'm pretty sure it's the only reason people really buy bluetooth<->OBD-II adapters. I was really very excited to give it a try.
It was easy to pair, the default code was 1234, which I'm pretty sure cannot change, but oh well. I paired it to my phone, check. I went into torque and it instantly pops up an error saying the device was pretty much guaranteed to malfunction, bad sign but I figured I'd give it a shot. I fidgeted with all the settings for a while just to get a reliably ball-parked RPM reading. After uninstalling and reinstalling torque, as well as disconnecting the scanner and removing it's profile from my phone (multiple times) I finally got it to work. Hooray!
So I took it about a mile up the road, just basic neighborhood driving. It reads (semi) reliably, but when I took a look, lo and behold 302 communication errors! I should have stopped right there, but I figured it seems to reliably report some data, the rest I could attempt to verify later (like mpg information). So I drove about 5 miles on the highway and my check engine light comes on!
I pull over, run the code scanner, no errors.. At all. So I drive the closest auto parts place that had a scanner that they would let me use, but on the way I smell burning plastic! I reach down feel the scanner and it's really, REALLY HOT! I rip it out of the port and go and get my codes checked, no codes, but my light is on. I had to power cycle my entire electrical system to get it to go off, now I'm stuck with an ECU that needs to relearn everything. Out of curioucity I go on my phone and found it had 4,000+ errors.
I am returning this after less than five hours, and I beg of anyone who's planning on buying one, reconsider. Just get the expensive one, the savings are not worth risking your several hundred dollar ECU.
About the coolest about it was having all those little blinky lights down by my gas pedals\....