BTW, your photography is amazing!!! Thanks for doing such beautiful work, that's an incredible gift!
I waffled between hydronic and electric radiant heat for a long time for my build. I ultimately choose electric, and it's turned out very well (WarmUp carbon matts), but Aquahot was the route I would've gone had I chosen hydronic. I went electric for a few reasons: 1) I wanted my camper to be fully functional detached from the truck, which has come in handy; 2) system simplicity, no moving parts, fluids, pumps; 3) dimensional advantages of carbon matts.
It's funny how these infrastructure decisions are interdependent. Since my camper is detachable, and I wanted redundancy, I decided that my two energy systems would be electric and propane. If I had decided to have my camper permanently attached, I would've gone with electric and diesel. I think I'd still use the electric radiant heat, but the Aquahot would've been a good consideration for hot water, with the ability to use both diesel and electricity.