As others have mentioned, the lacing system is comprised of a black cord that runs around the middle of the shoe and nylon webbing straps that go around this cord to provide lacing loops. This system is very exposed to abrasion and does not hold up well for canyoneering. I wore these down the Buckskin Gulch/Paria River trail, and they were pretty torn up by the end. After the first day, one of the straps failed. On the second day, another strap and the black cord failed. They stayed that way for two more days, but a third strap showed heavy wear by the end and likely would have failed soon after. Luckily, the mesh construction pretty much allows you to poke a hole wherever you want, so I was able to lace them unconventionally and keep going.

In all fairness, it was a pretty tough trail for shoes. We met another guy with some Keen water sandal/shoes that had a failure of one of the major straps on the first day. I don't know how new his shoes were to begin with, but on the last day of the trip, we found his shoes in a dumpster. He had also complained that they were coming off in the mud/quicksand along the river.My friend had some Salomon Tech Amphibians which killed his feet, but they held up with no damage. He also appeared to have much better traction than me in the mud, as the Maipos have a really shallow tread pattern that clogs up very easily. Neither the Salomon or Maipos had problems coming off in the mud though.

I will say that I do actually like this shoe quite a bit, just not for heavy usage. It is VERY comfortable, looks good, dries well, keeps out most rocks and pebbles, and does not take an odor after days of being wet. For lighter aquatic activities such as kayaking, wade fishing, occasional creek walking, etc, this shoe would be a good choice. It is also comfortable for everyday wear and breathes well on hot summer days. Just don't count on it for canyoneering, river hiking, or any other activity where the shoes are likely to be rubbed and abraded on the sides.