i went a few yrs. ago & DH & I wore them the whole time - we found them useful when getting out of the water (a lazy river) to view the birds on land. also, when doing the dolphin swim, i felt like i had a good grip on the water's edge while interacting w/ the dolphin. re: the bottom surface- when going under the waterfall in the lazy river, i tripped & scraped my knee pretty good in a shallow area so i would say it was rough.