RV GPS

I have a 1605 TM RV unit and it's no better than the GO 720. As a matter of fact the 720 has some features that have been stripped out of the 1605. One flaw in my 1605 is it will not retain a programmed destination overnight if turned off. The RV routing doesn't seem to be any different than the car routing and I have not had occasion to test the RV low clearance setting. Also TOMTOM doesn't tell you that when you go to update the map version it will not fit in the 1605 memory without purchasing a micro SD card to increase the memory size.