Bought a 2021 AWD EB Transit 250 High Roof 148" WB(not extended) in late March. Had Adventure Wagon in Portland install their RUV Kit 5/17. We towed our 21 up from San Luis Obispo and it got 1.5 mpg better than our Expedition with the same 3.5 EcoBoost & 10 speed trans. Probably because at 11 feet high the trailer is lower and the front of the van is more aerodynamic.
As far as comfort- it is way better than I thought due to the bus driver position. Lower back feels nothing after a long drive. That position transfers load from the back to knees which is what Saab was claiming way back with my 99.
So now we have a MIL unit