We have had both class a's and 5ers and lived in both long term. When we decided to go full time, the logical choice was a 5er and one ton dually.
One thing we consistently noticed was that the 5th wheel trailer usually had better storage in the bedroom for clothing and in the kitchen for food. Most motorhomes have a small it any pantry. Hanging space for clothes is usually better in a full time 5er.
With a motorhome if you have a mechanical break down, your house goes in the shop and you have to find a motel. With the 5er and truck, if it the truck has a mechanical issue, ERS will tow the trailer to a campground and the truck to a shop. Rent a small car for a couple of days and yo still get around.
I can get my Ford worked on in just about every city in the USA. With a a large motorhome you have to find a large chassis shop and they generally give preference to commercial trucks over RVS.
With the 5er and truck, I only have to maintain one driveline. About the only time we have a parking issue is parking garages where is left it with the valet service. When we came back, they had simply parked it over to he side out of the way.
But to each there own. But if the OP has never RV'ed, he need to rent one and give it a try for a week. They should also look at a gently used 2 to 4 year old unit rather than a new one. The bugs are pretty well worked out and the huge depreciation has been paid by the original owner.
Ken