I just recently picked up a pair of the Keen Payettes, but have only used them in the pool so far in my kayak. They're comfortable, have good ankle support.
I personally like having my feet closed off to sand/gravel. I'm a also a raft guide and last season I wore the NRS Desperado shoe, held up okay, but being used for guiding (Mostly Parkdale and Browns, with a few Gorge trips) and also while kayaking, the soles came apart at the end of only 1 season. (NRS customer service/repairs took care of me though)
I like the idea of having a more rugged and more durable bootie when in a raft, thinking that the Payettes would be a better choice over the NRS Attack Shoe.
If money is not an issue, check out the NRS OTB Abyss Boot...I mean, they're designed and engineered for Navy Seal(s), so, I would guess they hold up quite well in/on water as well as a good boot to wear while in the boat house, put-in, take-out, rescue situations...
OTB Abyss Boot
** This is only my 3rd season on the river as a kayaker and rafter. ** I'm sure that there is better info out there from the more experienced.