G+ like FB needs to achieve a critical mass of people who are willing to use it, FB was single college site in the early days remember before going public.
TBH, I was in on Google Buzz at a relatively early stage and it never had the same "appeal" as G+ although it had a great concept...but it was too finicky to get an easy grasp on. G+ is the successor and Google have clearly learned some lessons
However, I don"t think Google did themselves any favours by just opening G+ up in stages, I understand the reasons why but if a few hundred thousand had adopted from Day rather than just a few thousand, it might have wider appeal than it currently does. Google Buzz had the same problem...there was just no-one on it.
When it integrates seamlessly with FB, Twitter etc (and I can post in a single place and get it fed to all the sites) I"d be much happier. The current options ask for too much access rights for me to feel comfortable letting them at my various accounts.
With a wide range of friends and acquaintances it"s best (IMO) to access as many means of communicating with them as possible.
Some of them might not be on FB but be avid Googlefans or Tweeters...and I would like them to have access to my feed. So, at the moment, I have to multiple post and until a unifying app comes along that I feel comfortable with I"ll have to do it manually.