I did 9 miles of trail for the test. I had a few water crossings and plenty of sand and mud to test in. Pretty much the sandals held up well and I your feet are going to get wet anyways, might as well have wear something that will dry fast.
I wore a pair of bicycle socks with the sandals to prevent any chaffing. Everything worked well. Only problem I had was dirt would build up below my toes on my left foot. I soon learned how to quickly shake it out.
It's a litte worrisome to have exposed toes but I didn't have any trouble, but I need to hike where there are rocks and boulders to make sure though.