I remember back in my 20s every sleepless night rolling and turning bike touring and backpacking, tried 3/8", 1/2" foam, nothing worked, my body as a side sleeper, no extra padding on me, just cannot sleep with my hip bone/shoulders digging into the ground. Then I got my first thermarest, and actually slept for the first time camping, was great, still is. Wish I could use closed cell foam, really do, simple reliable, strong, durable. But I cannot function without sleep, especially backpacking. Only time I've had a flat inflatable was when I stumbled into a cactus one tired hot sweaty day, thermarest, old big size, was strapped to outside of pack, pierced several layers. That one actually had enough padding so it wasn't freezing though, but it took all the patches to make it work.
Also had that same one in storage, had never leaked since then, but cat found it and liked walking across it, so got tons of holes, but that's the only actual flats I've had with these.
But I really clean my spots before putting down the ground sheet, I use the ground sheet to find the sharp thingies, that's actually one of the advantages of using one, it's very easy to feel them when you pass your hand over it, remove them until there aren't any.
Haven't done as much stuff as Bob G probably has, but haven't had any issues with thermarest.
Got a neoair, and I definitely would not go lighter material than it uses, you can' t make magic happen with materials, at some point things are just too light. Plus buying the first year beta test product is never a good idea unles you like being the person to find the problems that will get fixed on the next major release version. I dont' like that process, got tire dof it years ago from doing software stuff, now I'm happy to let others suffer and benefit from their early adopter experiences.
I am using with both the thermarest prolight and neor air always placed ontop of 1/8 or 3/16 closed cell foam though, I don't trust that thin material at all, got a gossamer gear pad to put under it, just weighs a few ounces. When I compare the original thermarest 1.5", tough, durable, unless you subject it to cactii and cats, the light 1" one they did after, both the green topped ones, with the prolite and the neoair it's totally obvious the new stuff is going to be weaker, so I treat it that way. The closed cell thing is a great sit pad, crash out and look at sun/stars mat too, and makes a good backpack foam frame, plus adding some r value, very multiuse, that seems a good way to go, I'm happy with it.