Having had a play with Google+ for a couple of weeks I like it. I can't bear Facebook, its user interface is too cluttered and I have never really got in to it. I also dislike all of those game generated status messages which clog up the works.
If Google can keep plus clean as they add features then I believe that they could do very well with the techie crowd and from there plus might spill over to their less techie friends. Having said all that there is a lot of inertia keeping people on Facebook.