Love my Exped Megamat 10. Not cheap (paid like $220 four years ago) but it’s extremely comfortable. I love that it allows me to sleep on my side or in my back.
If you are car camping, look into the Exped MegaMat line. I have the single LXW and used to have the double LXW before upgrading to the Duo Max. They are hands down the reason I'm willing to camp. They have great insulation and cushioning. Putting your pad on a cot will also help your wife because it's more like a regular bed and you don't have to get up from the ground.
I use a Exped Megamat XLW, it's 30.3" wide. I'm a side sleeper and use a quilt, but I tend to roll a lot during the night, and this pad works great for me.
No IME better materials and design do make for much better sleep. The stretchiness of the material its made from and the details of the shape affect how well it conforms around my body, how noisy it is, how easily I slip off it and how much of the surface area is really usable.
It's too big for your use case, but at one extreme, the Exped Megamat 10 is more comfortable than most of the real beds I've ever slept on. On the other hand I used to have an REI inflatable of similar dimension that I used once and immediately replaced because every hour or so I'd wake up from either the noise it made every time I moved or from sliding off of it.
Gotcha, I do think there are some differences in back support, e.g. stiff outer materials don't conform as easily so they get big wrinkles and creases and don't give as even support as thinner more flexible materials or, better yet, stretchy materials, and placement of baffles affects where it's thick and where it's thinner, which could make it better or worse for someone's particular back. For me, the amount of air in the mattress makes a big difference too - I do best when they are pretty firm with just a little give. But as you suspect, there's also a kind of sameness to air-mattress type support that's going to be part of pretty much all air mattresses, especially if they're at all underinflated.
Some stores have floor models of all their camping mattresses already inflated and available to try, if there's one like that in your area your best bet will probably be to go lie down on a bunch and see how they feel. For me, the support varies a lot in a meaningful way. But there also might be folks for whom none of them feel great, in which case a different type of pad might be better.
Bud755
