I do use google+ actually. But it's more of a news/discovery site for me. I don't have many friends on there so I basically just check back now and then for news or when I'm bored. The circles makes it easy to do this and the "what's hot" circle is interesting sometimes.
I don't have facebook, mostly because I don't have a need for it. If I want to talk to my friends I'll skype them :3