For what it is worth, I am a mechanical engineer who will never be able to retire...
I bought one of these:
My intention was to drive both the drive and steering motors on an RC car I was hacking. I have also hooked it up to some motors out of an old printer, as well as steppers and it seems to work for everything.
My only caution is that the switch settings are not particularly well documented and there is one combination of switches that is bad news (you end up applying 5V to the Arduino's 5V pin).
I have bought a bunch of sensors and boards and general electronics (including the motor shield) from China and have not yet run into a quality problem. Biggest issue is having patience waiting for stuff to ship, and documentation is usually bad. But for the most part you can find things elsewhere on the net (for example, with the shield above, anything intended to work with an L298N dual H-bridge like sketches etc. should generally work fine).