As noted above, RV is a generic term that refers to motorhomes (MH), travel trailers (TT), 5th wheel travel trailers (5er), pop up campers (PUP), truck campers (TC), etc.
As far as which is best for you, only you can decide based on how you intend to use it and your personal preferences.
MH - many like them because you can move around in it while traveling. But you will generally need a vehicle to tow behind it (toad as in towed) to get around after you get set up in camp. A MH will typically be more expensive than the other type RVs. Plus there is the maintenance needed for the extra engine/drive train.
TT or 5er - with a trailer you will need a capable tow vehicle, maybe 350/3500 truck (1 ton) if it is a heavier trailer. But that truck will also be your vehicle to get around after you get set up in camp. Smaller/lighter trailers can be pulled by lesser vehicles including SUVs, or even cars if the trailer is light enough.
We chose a 5th wheel trailer because of our usage. We use it 30-40 nights per year, but are typically only on the road 10 days or less per year. Did not make sense to have a motorized vehicle (motorhome) that would be driven 10 days per year and sit idle 355 days. But the 5er does still give us the floor space of a large motor home.
Rubber roofs have been around a long time. I don't see them as a particular concern.
I think you can find good entry level RVs. Sometimes the difference between entry level and mid level is the little things like fancier woodwork, nicer fixtures, larger appliances, etc. Not necessarily better quality, but nicer to look at.
Reading a lot and asking questions about particular brands/models and you can find out how satisfied/dissatisfied people are with them. Bear in mind that you will find people happy with most all of them, and people who have had problems with most all of them. Just have to weed out the best information you can.