Just got back from a small RV show here in town. We spent a lot of time looking at 5th wheel's. You get a lot more space inside if you spend the money. If you have several teenagers in your crew, I can't see any other way to chug down the road. If you have dirt bikes or other toys, they can offer some unique advantages. Spend enough money and you get very cool auto leveling systems. Everything we looked at had room for a washer / dryer. All of that stuff .... not so much in a typical AS trailer.
That said, there are a couple of downsides:
1) That great big 5th wheel is great big. The cool tall ceiling means a tall roof. That plus slab sides will be fun in a crosswind.
2) The great big 5th wheel is great big. Looking at them with all the slides out, they take up a lot of side to side room on a campsite. I would guess that we would have had trouble at about 2/3's of the sites we camped in this summer. Indeed I probably would have picked other places to go because of that.
3) That great big residential fridge is exactly that. It runs on 120V. Keeping it cold while you roll down the road for a couple days ... yikes ....That's a lot of battery power into an inverter ( = propane makes more sense to me).
To me, the 5th wheel makes a *lot* of sense as a mobile semi-permanent home. Chug here and stay a month, chug there and stay for a couple of weeks. Live that way 9 months out of the year. Pick you sites as a place to park rather than for the view. Drive around to see the view.
Even a big AS trailer is a bit more mobile than a big 5th wheel. Ground clearance on the AS is about the only place the 5th wheel might win. Drop down to something in the 25 to 27 foot range and you will fit lots of places the typical 35 to 45' 5th wheel isn't going to be happy getting into.
Finish / workmanship / interior wise, we didn't see any 5th wheels that were exciting. Lots of doors that didn't latch. Lots of warped counters. Lots of little issues. Equally, my AS is far from 100% perfect. It's way better than anything I saw today .... How much does that matter? ... who knows.
Very much a personal decision ....