From what I hear (from the few people I know at Netflix) since there is a lot of fear that you can be fired at will, no one takes a vacation at all. It actually makes sense too, if one member of the team does not take a vacation but you do then you will come across as the one "slacking off". On the other hand if you are a set number of time off days you can take them without feeling guilty about it. Of course it depends on the culture in the group as well but I am very skeptical about it working in a company the size of netflix.