I know this topic is old....
I own a pair of these. EVERYONE should own a pair of these!
I absolutely love them. I own a pair of Sprints, and this weekend I'm driving 2 hours to my nearest retailer to buy a pair of KSOs. I would order them online, but I'm in a hurry to get them because I want them for my upcoming vacation. They are very comfortable. I don't like toe socks or things between my toes, but these don't bother me. Honestly, I don't even notice. The material is really thin and breathes well so it would be hard to notice I think. The soles are sort of fit to the way the human foot is. These are perfect for hiking trails or walking on concrete, but walking on gravel or sharp pointy little rocks will hurt your feet... just like walking on them barefoot would.
The sizing is tricky. It took me 3 times to get the right pair. The first time I ordered the Classics, which I didnt like, and the second I ordered Sprints (which I recommend) but they were too small. If you are ordering online, I suggest ordering two different sizes and then just sending one back. They have great customer service.
Yes, they are expensive, but SO worth it. I'm really cheap. I only own one pair of black flip flops that I've had over two years, and these fivefingers, which are my favorite purchase ever.
I wore these all over Yosemite in May and had no problems. I guess the only downside is that people everywhere will stop and ask you about them. I didn't mind though.
But anyways, they are great. Here are some pictures of me wearing them all over the valley:
I photobomb my girlfriend's pictures with them
These were great on the mist trail. Everyone else's shoes and socks were soaked, and with mine it didn't matter. Not to mention, the trail is pretty slippery and I had great grip and was really able to feel if where I was stepping was stable or not.