I can't count the number of bitching posts about the complexity of circles. But they are as complex as you make them.
You can tweet and blog (full-public post), send restricted messages (circles), or even private messages (single user).
I think the more interesting question would be "how many circles do you actively use"? I went circle-crazy and categorized a ton of people, but really only use "Friends", "Acquaintances", and two other circles -- both of which neatly translate to real circles of friends.
I would have settled for "always or almost always", "sometimes", and "never or almost never"—the choices and the number of them were a bit confusing, and I don't think anyone keeps a statistical average of the number of times they share publicly to warrant that number of choices.
I believe I wanted Google+ to fix this problem for me, I was expecting a place where I could do my private life (with circles) and improve my professional life (public but without annoying some cirles of the private life).
In the end, I just feel lost not knowing how to use that pretty thing...
google identity = work (buzz, profile, gmail, twitter) facebook identity = social
i think most people will continue to use existing social networks. we'll post appropriate content to our audience, and the audience at each network has a different tone. this is natural, i think.
But they will pick it up soon, no doubt. The need is there, technical possibilities are endless, so submit your feedback as I did and wait.
Separate websites for each social context makes my life easier. LinkedIn is professional. Facebook is social (well, before my contacts got mixed up). Dating websites are personal.
Google+ doesn't provide a strong visual indicator to help me switch contexts. I'm not absolutely certain that I haven't mixed up one of my business contacts with my personal ones. Add to that the chance that something gets sent out publicly by mistake and there is absolutely no chance I'll use G+ for anything beyond Twitter with pictures.
However I really, really would like to tag what I make public. As things stand I censor myself to only talk about things that I think are of more general interest. And this frustrates me to no end. If there were some option to categorize my public content and only send it to people who want it, I'd be using it in a heartbeat.
A few, I knew I only wanted to target a specific audience, and so that's where they went.