I brought two of these as my underwear on a three-week canoe trip, they not only survived but treated me very well. I loved the comfort and feel of these, and I continue to wear them to this very day. I never had a problem with them stretching out, but maybe because I have a boy-shaped body?
I don't normally buy [$] underwear, but I splurged on these because they were so cute. I also thought that since they were made by Patagonia that they would be of high quality. At first they are really comfortable, but as the day goes on, they stretch out (a lot) and lose shape and begin bunching and rolling up. Not worth the price (or the discomfort)!