I think Google+ is great. Ever since I abandoned Facebook a year ago, I have been wanting to share content with my closest friends. My problem with Facebook, at least at the time, was that I could only share content with everyone I was connected with. With Google+ I can create dedicated circles and target my content. After all, I am a different person when I am with my family, different when I am with my friends and different when I am in the workplace. Do these worlds merge on occasion, of course, and it is always nice to share across social circles. However, I think the approach Google+ has taken reflects this real-world phenomenon.
That said, I think a major hurdle with Google+ right now is the public profile. Currently Google requires that members have a public profile with some basic information, such as a name. The problem with this idea is that anyone can place you in their circle. I was just added by someone 1) whom I have never met and 2) whom none of my friends have ever met.  This notion is similar to how Twitter functions, but it is more alarming since 1) everyone on Google+ must have a public facing profile and 2) Google+ hopes to integrate every aspect of your web identity from documents to photos. It is possible to block users and I have already blocked my share of social spies, as I call them.
I still see a lot of potential with Google+ and I hope it begins to pickup more steam. I have been reading that, although the initial buzz has been great, the usage has dropped off considerably. I also hope to see a better integration across Google products such as YouTube, Blogger and Documents.