In reply to daftendirekt:
We've had one for a year or two, had to downsize from a SNAP burrito, which would not fit in our car/house...
As other's have said, it's basic, but fits in car boots and carries very easily (NB. the buckle makes a great bottle opener, useful to know after spending half an hour trying to open a beer with a coin). Also you can put it either way up, so the bit against your back doesn't have to get dirty.
Granted, it might not last as long as a DMM etc. And I wouldn't want to drop 20' onto it (unless it was on three feet of soft wet lakeland grass). But if you're not going to be using it much, then does it matter?
P.s. We use ours about once a week in winter, prob less than once a month in summer and the foam still feels fine.