As for the stopshop unit.
The issue is not so much with the quality of the device (although for that price I am not convinced that its so hot) the problem is the operating system is Windows CE..
Windows CE is a frikken disaster when it comes to memory management, and as such, badly written programs tend to lock up the unit, stuff does not work ect ect...
This is NOT an oem headunit that has been tested by 8,000 germans in white coats, this has been assembled by the chinese for 1 dolla and some rice.
Again, I am not saying that this is crap, but you have to be fairly tech savy to fully operate/deal with this things crap.
I am going to order a unit as well for the //M when I have some money again and will provide you some feedback, but this is not for the faint hearted.