Do You Use a Skin Brush?

The first time I heard about something like this was when I was introduced to the Clarisonic. It's kind of expensive so I haven't bought one for myself yet, but my facialist uses it on me and it feels like it's doing a good job at deep cleaning my skin. Other brands have come out with similar, more affordable tools, but from reading reviews Clarisonic still seems to be in the lead.

My question is: Do you use a skin brush tool? What brand do you use? Do you feel it is worth it?