I'm a small careful female, and I think the UL version of the Synmat would be OK in my care for extended trekking.
However, my hubby (-a large 'chubby' fellow with less patience) has the more durable Downmat. I'm not sure I'd let him loose with the UL version.
I've not handled the heavier weight Synmat.
Edited: 12/06/2012 at 10:41