An RV type GPS is worthwhile and an improvement over a non RV model.
However its not foolproof.
It will not tell you what gas station to use nor will it direct you to avoid rush hour traffic.
It will attempt to take you on an RV safe route and avoid small streets and low clearances.
I have a Garmin RV 760 with the integrated BC-20 backup camera and it has worked well for 3 years now.
However I generally review the suggested route and ensure it is the most direct way. For the most part the route is chosen by the Garmin meets my needs.
Nevertheless never trust any GPS 100%. Especially while towing.