I don't like it for myself because I don't work well that way. I don't like working at companies that use pair programming because most of the code I've seen come out of pairing sessions is not very good. I realize that's likely to start a religious war in certain areas but I've been doing this for 20 years and that's been my experience so far.

I think pairing sessions can be great for teaching or for getting some needed distance from a problem, but as a mode of production I haven't enjoyed my experiences with it.