My Jayco J Flight 23RB is the old school "stick and tin" (wood frame, aluminum frame) type travel trailer. We've had it almost 2 years now. So far it's been fine. My previous trailer was a "light weight" trailer with aluminum frame and Azdel backed fiberglass sides.
The fiberglass trailer was a little easier to wash, IMO, because it's just a little easier to wash a flat surface than a corrugated surface.
I think the fiberglass sided trailer was a little warmer. My current "stick and tin" model is harder to keep at a set temperature. Of course this my partly due to my current trailer being a couple of feet longer and a 1/2 foot wider.
I can't speak to ease or cost of fixing either type of siding since I never had a problem with the old one and haven't with my current one either.
As has been mentioned, the floor plan is what's most important. I sold my prior trailer only because it was too small for the two of us. Our current trailer is just the right size for us.
If we had had the next model up in the now defunct Skyline Koala line of trailers, we'd still have it.
