I work in an office of 15 IT people and only 1 is using Google+ Everyone else has zero interest. The one guy uses it very enthusiastically, but a small core of G+ fanatics will not make the service a long-term success.
Anecdotal evidence of course, just pitching in my 2¢
I had considered giving it a cursory look, but then they started the whole "real name" thing and that clinched it for me. I would have stopped using it after the initial inspection anyway though, so no big deal really.