In my time, I've camped with people that own Ultimates, and people that own Tvans. When researching for our first camper we looked at both. The Ultimate had the advantage of a moulded design and being well up off the ground with plenty of bed space. The Tvan seemed to be an engineering masterpiece but the bed space a bit too claustrophobic for our liking.
I know it shouldn't make any difference, but there also appears to be a distinct difference in disposition of the two groups. Just can't quite put my finger on it tho🤔