Mine were a Christmas gift. I did not take it slowly enough so I strongly urge anyone to transition very slowly. If you still want to get your mileage in, do it in your other shoes, but take your time transitioning to the minimal shoes, especially if you area flat-foot runner. That's where I injured my ankle, switching to running on my toes in the vibrams.

I got them for Christmas, and by mid-February I had stress fractured my left ankle. I took a month off for it to heal, which wasn't long enough. I immediately injured it again. Since they were expensive I wasn't going to give up on them yet. I waited a couple months, then tried again, this time taking it very very slowly. I ran only ten minutes at a time, with a few days in between. I increased to 15 minutes. Any time I had any soreness or discomfort I backed off and took several days off.

This morning I ran for 50 minutes!