I barely use it anymore, for three reasons.
1) The Content has changed
Hardly anyone from my circles "blogs" on it anymore. They use it like an impersonal Facebook – reposting articles from other places on the web without adding anything to it. There are a few people out there who share and add quite a bit of editorial content, like and and sometimes , but the vast majority? It's just a link to a funny cat picture or article about (x), with nothing insightful or personal added about it. I appreciate , and the dynamic duo of and so much because (unlike so many) their content is pretty much always personal.
2) Google destroyed Hangout Discovery in 2012. For the first 2 years of G+, I had a circle of HUNDREDS of people who would hang out two or three nights a week. Epic 6 hour Hangouts. Sometimes drunk. Sometimes naked. Sometimes both. We'd leave the Hangout public, and random people from all over the world would sometimes wander through our hangouts – much to their confusion, more often than not… Then, in 2012, Google changed the way Hangouts appeared in people's streams (so that they basically didn't appear in people's streams), and within a month the weekly hangouts were completely dead.
3) We never got the (vaguely) promised API. I can pull anything I post to Google+ into my WordPress Blog, but I can't go the other way. So now that I'm a fulltime RV dweller (currently in Sacramento), and have a lot of content and a limited bandwidth connection, and without an incoming API, all the interesting things I've done in the 6 months since I hit the road have wound up on YouTube, Instagram, Facebook, and my WordPress site (Yarrvee.com)…but have been locked out of Google+ unless I take the time and effort to post them by hand – which sucks because I often upload videos when I have a good connection, then schedule them to go public 3-4 days in advance when I know I won't have a solid connection. No solid connection means that I can't hand-post to G+
The platform had a ton of promise in the beginning.
These days, it feels like Ingress (which started out as a side project from a very small team) gets more love than G+ (which started out as a project that was supposed to 'revolutionize' Google) does.
That makes me sad.