I've had a pair of KSOs for about 18 months. They are a struggle to get on at first, the problem is getting each toe into its proper toe condom. But with a little practice is gets pretty quick.
It does take a while for your legs to get into shape, as most people are used to a heel strike, this is especially true if you run in them. Your brain is going to force a front of the foot strike, without your permission. If you want to run in them, go slow, unless you have been running barefooted.
I no longer hike off-trail in them or in rocky areas, as my little toe kicks the occasional rock or out-cropping. I like to do short runs in them. It is almost barefoot running, without the need to toughen up the bottom of your feet. You will feel most little things like pebbles and such. I can run/hike on fine gravel roads without discomfort, but it is a funny feeling that takes a while to get used to.
If you do not like to stop to talk every hiker you meet on the trail or stop and talk to strangers around town, then these are not for you! Everyone wants to ask questions.
They do get stinky after a fairly short time. They have to be washed periodically. For really light shoes, I prefer XC racing flats, which are generally lighter than these. I am using flats less and less, because they do not last long in the terrain I frequent. For most hiking I always go back to my Salomon trail runners. I am pretty much done experimenting with shoes, overall the Salomon's do everything I need. The KSO's are nice for running (not on asphalt).