I just wore these on a four day canyoneering trip. With a 30 pound pack, these shoes were comfortable and stiff enough. We were in and out of the muddy water for 40 miles, and the shoes drained well and my feet are blister-free. I have wide feet, and I wore both thin and very thick neoprene socks, and the shoes comfortably accommodated both. Two problems, though:
1. The heel strap slipped. There is a little webbing strap that cranks down on your heel, and it comes loose pretty quickly, causing the shoe to flop up and down. I put a safety pin through the webbing and that held up for the trip. This shouldn't be necessary, though.
2. The lace busted! These laces are specialized and difficult to replace - this is a huge problem! After about 10 miles in muddy water, the abrasion of the silt in one of the lace eyelets wore through the lace. These are tough conditions for the laces, sure, but these shoes were sold to me as canyoneering shoes. This shouldn't have happened.