The first review that pops up with the link you sent pretty much says it all. Save your money.
On that same page there is an ad for the AllStays app. That one is is worth the $9.99 and is probably the best campground, fuel stop, Walmart finder app available to you.
If you want/need a GPS, look at the Rand McNally 7720 or the Garmin Dezl 760 - both do RV specific routing. Lots of threads on both.
Roger & Mary
2014 Tiffin Phaeton 36GH
2012 Honda Fit toad