I, too, read the glowing review in Highways and thought the RVND 7725-LM sounded great. I have a Magellan and a Garmin, but those units somethimes send you into places you don't want to be with a trailer.
I bought the RVND and my first trip was to Key Largo from Boca Raton, FL. The unit put me onto I95 for a long way (to Atlantic Blvd) instead of the way I normally get to the FLA Turnpike, so I thought it must know something about the ease of getting on the pike there or something. Not true, though. Coming back, I was already on the tunpike coming out of Homestead and the unit directed me to go into downtown Miami, get onto HWY 1 and then to I95. I used to work in Miami and anyone who knows that route knows it would be your worst nightmare with a 40' trailer.
I had already input all the parameters about my vehicle and said I wanted the fastest route and tolls were OK, so I was amazed the GPS logic would be so stupid as to route an RV into downtown Miami! We tried saying "avoid freeways", so it told us to take HWY 27 to South Bay and then come back east to I95. That's neither the fastest or the shortest route! I couldn't get it to shut up about I95 while going up the Turnpike, so I had to just shut it off!
I like a lot of the features of this unit, but I'm going to send it back because I fear where it might take me if I didn't know any better.