One item that everyone misses, is where do they get the MAPS & POI's (M&P)
Not all GPS providers do there own M&P. My suggestion is to look in the setting and locate the "About" option. See who provides the M&P's. Most GPS units are Window CE operating system. If you like how 1 system operates, then search for that M&P software in that unit. Example, the Rand NcNally for Rver's uses
Navigon for M&P.
For me I like the I-GO-Prime. Using the latest in brain power I took 2 old units and loaded the software into the 2 units. My In-dash unit and portable unit now have the same M&P.