We used a tablet in our old van,but when we were away in October in the new van I used my phone linked to the head set which worked but my phone was plugged in all the time and was getting quite warm,we used Google maps but you can't programme in the dimensions of the van and had a few tight squeezes and had to reverse a couple of times due to low bridges.
Our new van has a sat nav system in it but with no maps card which is about £200 and according to the dealer we got the van from it's not very good,so I'll keep the £200 and look for an alternative.
We uses to use a Garmin sat nav but same problem not being able to put in the dimensions and as soon as we came off the ferry or train it went tips up even although I updated the maps before we left.
I'll have a look at the others you mentioned. Thanks