When we first set up our ute back camper we went for fixed panels on top. Great cause I didn't have to set it up each time, but pain as you had to park in the sun to get maximum out of it. We now use the fold up type, yep, I've got to put it out when I want to use it, and I mucked around a bit at the start with a clamp meter to work out how long the cable can be before it loses ooomph, but now I can park the camper in the shade and run a lead out to the panels in the sun. It also stays clean better, opposed to me having to clean the old one when it was on the roof, and at 2.5m, it was a pain reaching it.
It's not like the fixed panel was doing much when we were driving as it is all connected to the car and charges off the car when under way. And, as a bonus, I also drape it over the bimini on the tinny when doing big days on the electric with the fridge in the boat flicking for Barra.