I just bought one of the Chinese cheapies off ebay but haven't had gotten around to mounting it yet (need to do some cutting and bondo work to adapt 2 din unit to 1.5 din slot).
Physical quality seems good, the buttons don't suck for example; the OS is vanilla Android 4.x and Play store compatible so my fingers are crossed that it will work out well. Hardware spec is decent.
Once you have a decent generic hardware platform it's really up to the software at that point.