Ok,
To close out this thread I settled on the 23u. Came down to price, availability for the 450 chassis. I climbe up on a sun seeker fiberglass roof also, and found the fiberglass weak in spots, easy to bend or crack , very thin. The tpo Thor roof was solid everywhere I checked. Really didn't see much quality difference besides the sealed holding tanks on the sunseeker. Cabinets are low quality in both e450 same in both, and very few out of state usnseekers available when I bought.
I did notice online several 120k plus Thor models, no sun seekers. That might not be a ding on sunseeker, maybe not enough of them out there, but the Thor models with high mileage still looked serviceable.. as was my funmover.
Thanks for the tips.