I also got a elm327 dongle from dx for less than €8 shipped a few months ago! Typical low grade electronics ****, but I wanted to try it out. Coupled to the torque pro app however, it's quite a powerful little cheap combination and it seems to hold up! I much prefer it to the low end dedicated scanners out there, because of the ease of graphing and plotting all the pid's, and the quickly accessible DTC info. I use it on an old android tablet and the big touchscreen sure beats the cheap two button design + it's wireless over BlueTooth. If you load up the tablet with a bunch of service manuals and wiring diagrams and know how to diagnose a car, fixing most engine problems becomes quite straightforward!
Don't expect too much out of it though. Works only on generic obd, but it supports all the cars I used it on (6 different makes so far). No enhanced, manufacturer specific PID's, no airbags, suspension,... That stuff is beyond my capacities as an amateur anyway.