Originally Posted by FALAGAR
It's fine to use MapSource if you want, but do so at your own risk. I want to point out that the image creation code in MapSource is very dated. It might or might not work properly on the device. They have been dozens of fixes since MapSource 6.16.3 was released.
MapInstall should also be faster in image creation and transfer (depending on the type of map and device) because of performance improvements we made. MapInstall supports nMaps (more than one supplemental map), without having to manually rename gmapsupp.img. So the official recommendation is to use MapInstall, not MapSource. If something is wrong with a map on a device (mainly with routing) and you created the image with MapSource, I'd try again with MapInstall to at least eliminate one possible point of failure.