The rubber roof will need to be replaced sooner or later though usually you can expect at least 15 years from one if it has been maintained decently. Can stretch it to 20 if you paint it a couple of times.
The aluminum is good for 50+ years. Just need to keep the seals around the penetrations maintained.
TPO was questioned at first but after 20+ years of use seems to be holding up very well and may match aluminum.
I would take a look at the Northern Lite even if the one near you is over priced. Would let you see what the floor plan is like. You may like it and want to keep looking for other units.
My first camper I drove 350 miles to look at it. My next one I may end up driving 500-1000 miles to get it. Down here, truck campers are rare and my floor plan selection has been narrowed down to a couple which makes the pickens even slimmer.