I own a 5er and have thought the same question before. We went to the local RV show this weekend and looked at of lots of course RV's. Since we own a 5er we naturally looked at what we might want to upgrade to in the future. We found several in the $53-63,000 range that would be doable for extended stays. 2-3 months at a time trips. Most were around 35' OAL, with good holding tank capacities, full profile fronts and great closet space. Several had nice 48-60"x30" showers.
After cruising thru lots of 5ers's we decided to finish the day and make our way to the exit and stop at MH's on the way out. We went thru 8-10 or so MH's with the highest priced one near $140,000. Theses were discounted prices too for both the MH and 5er. Anyway as we made our way thru the MH's we noticed the lack of counter space, interior storage and poor seating configurations. Also most of the bathrooms were naturally split but overall weren't as accommodating as some of the 5ers were.
In the end the wife and I came to the conclusion that for less money you get way more with a 5er and you still have a vehicle to drive while staying somewhere. All the 5ers we looked at except one had 4-6 pt leveling, same as most the MH's did. So a wash there. For us anyway we crossed MH's off the list. Less room inside, less storage inside and the typical poor seating configurations were the downsides. Only plus to a MH I could see was the outside basement storage. We would still have to tow something, so setting up would IMO actually take longer as you would have to drop the toad if you're in a back in spot. Pull thru are a wash.