I have found that for my purpose the Deepsleep mat is a bit more narrow than I expected, but this may not be the case with everyone. If you are a larger-built person, I'd be cautious. Laying on it flat, my arms do still come off the sides, and if I were to roll over, I'm definitely going off the edge. Sleeping on my side seems to be okay but not always as comfortable. Again this is subjective and my own personal opinion. The thickness of the matt does seem to be sufficient, but after a few night...