GPS units are great WHEN THEY WORK
PROPERLY.
EVERY GPS unit will, from time to time, give erroneous information (My Rand McNally often tries to get me to leave a limited access highway, I guess because of heavy traffic, when the local roads are worse. It also has tried to route my 12'5" high Super-C onto PARKWAYS in NY). Paper maps, particularly the Motor Carriers' Atlas, seems to have MUCH fewer errors than ANY GPS unit I've tried (and I've tried most of them).
I currently own a Rand McNally RVND 7710: Bad hardware and software; $400 wasted.
Rand McNally 720 software: Preinstalled in my Super-C; some improvement over the 7710RVND but I would not have paid for it separately.
Garmin dezl 5": can NOT enter how much propane I'm carrying.
Copilot software on my iPad: can NOT enter much propane I'm carrying; can't get it to switch to "Night Mode" on my iPad. Poor customer support.
TomTom car software on my iPhone: for cars; NOT RVs / trucks
I believe TomTom now offers an RV product. I have not seen it yet
The "new" Copilot RV App limits length (either 40' or 45') NOT suitable if you have a TOAD. There was also a weight limitation; NOT for BIG RVs.
One of the RV "social" websites offers "routing" It is
NOT routing for RVs!!! After getting dangerous routing, I wrote to and questioned the moderator. The lame response was, that his site was trying to facilitate RVers meeting, but NOT driving their RVs to make the meet! Absolutely insane. There was
NO warning that the routing data provided may NOT be suitable for RV sized vehicles and, may put a large RV onto roads that were unsuitable / unsafe.
A SMART RVer will use MULTIPLE sources BEFORE they get into trouble. Google Earth, Rand McNally Road Carriers' Atlas, as well as GPS units / software, can be used to cross check. Yes, it takes time to do all the extra work (especially at first). With time and practice, it will get done quicker. We're all driving large, expensive "toys". It's MUCH better to prevent trouble than it is to recover from it.
I shall now step down from my soapbox.