Great with Vibram Five Fingers
I wear these as a liner sock for hiking, and they have eliminated a long reoccurring blister betwixt the toes.
I also work out and run in them, usually wearing Vibram Five Fingers. I just found that I enjoy VFF's better with socks than without: less swamp foot, and no blisters.
While I also own the "performance" model of these socks, I found them to not be durable enough. This model, the "outdoor" is a bit more durable, provides slightly more padding, and, to me, seems to breathe a bit better. I suspect some might find this model to be too thick for use with VFFs (which are usually worn barefoot), but they work fine for my skinny toes.
Great product, I just wish they were a bit less expensive.