In reply to Oscar Dodd:
I've got an ultralight Neo Air and I've never had a problem but I am paranoid it's going to get punctured, it really is crisp-packet material.
I use a thin foam mat underneath it. In winter conditions or if I think it might be rocky I'd use a standard foam mat underneath it.
Foam mat + Neo air us warm, comfortable and some emergency resilience - so if it popped things would be bad but not the end of the world
It is overly expensive and I probably wouldn't buy one again, but it does pack really small and light!
Post edited at 07:46