Never understood why some place so much importance on the unit being 100% usable with the slides in. While in transit there is no need for the living area. No need to sit & watch TV. If at Walmart put the slides out. You are taking up the parking spaces anyway.
Being able to use the toilet with slides in is important along with being able to access the fridge is very nice.
As far as making the model selection goes, doing the research is very important. Buying mistakes & flipping from one unit to the next gets extremely expensive. If buying for yourselves as a longtime traveler, don't buy a family unit. Those kids/grandkids are adaptable & can sleep most anywhere. Don't be impressed with the superficial bling. Stuff like self leveling...Whoopie!!!! It is something else to break down.
Buy your last unit first. Buy a slightly used top quality at the price of a new mid market unit.