I tried to join lisnpn, but I didn't get the e-mail with the confirmation code yet. And it's for new professional, which I am not. I guess I'll just wait and see what happens.
I haven't really spent much time in Goolge+, maybe it'll improve over time but I found it clunky and slow. I also found there are not a lot of people on there that I know to add to 'circles', and many of those that are haven't bothered to post anything, so I wonder if it is a long term prospect once the hype blows over.