I actually got to put my Seal Skinz to the test this weekend while trying to fish out a disc out of a nasty water hazard. My shoes are a nearly blown out pair of absolutely non-waterproof Salomons, and my right foot got mostly submerged. I thought the Seal Skins leaked on me, but it was just the cold I felt of my shoe filling up with water. I honestly didn't expect the socks to work that well, but they did. Granted, they're still pretty new, I've worn them maybe 5 or 6 times, but they actually worked as advertised.
That reminds me though, gotta post in the "Lost Discs" area.