I'm a member of both, but don't use either much. Only got an invite to Google + to see what it was all about and how they have approached it compared to Facebook. For professional use LinkedIn is a much better network to use as people take it much more seriously. Facebook is just a global gossip playground populated by teens and women wanting to nose into everyone's lives. I also hope Google+ doesn't end up just being a copy of Facebook and instead does something more useful for people who are not just wishing to gossip, but instead use it for project collaboration, sharing information and networking.