We have a Snooper loaded with the Caravan Club database, it includes continental sites as well. It is configurable for Motor Home or Caravan and outfit size. It is very good for navigating to sites, and avoiding unsuitable routes. A useful feature is Multi routes allows an itinery to be pre programed. The bad news is the menu system particularly the Multi Route facility, I can only assume that it was designed by someone who has never used its Multi Route mode for real. The good news is that updates for life are free.
I still have my old TT 720 which has been excellent both in the UK and Abroad, I keep it as a back up.
But I decided to update to the TT Camper & Caravan, with hindsight I would not have bought the TT Camper & Caravan version but that's just my personal opinion. It has no Itinerary Planing, only 3 'Vias', can not be used with 'Tyre' and in anything other than 'Car' mode it heavily favors Motorways (which not not be 'Avoided')
We used to have a Medion GoPal but when it became time to update it, it was only marginally more expensive to have a TomTom with life time map updates so that is the route we took. The TomTom I chose does not have a facility for inputting the length, width, height of the outfit but, apart from that, it does everything I want it to do.
Before setting out with the caravan, I trace the route on Google Maps then, if there is a road that looks a bit "iffy", I look it up on "Street View". That has saved a lot of problems and we have been able to modify the route to avoid the pitfalls.
The only big snag is that, because some of the files on the TomTom map updates look like a corrupt file to my Bullguard protection programme, the firewall has to be switched of for the length of time it takes to download and install the new maps (about 25-30 minutes). Not ideal but it seems to work OK. I am also protected by Norton which came free with the laptop.
The TomTom is certainly faster than the Medion at recovering should one decide to go a route that one knows rather than the route the satnav has worked out.