A couple of years ago I joined the Google+ trial.
I hoped the circles would solve the issue I have with Facebook - one account for all your networking instead of one site with multiple accounts, each for a different networking environment. The circles wasn't what I had hoped for, but I decided to give G+ a chance.
A few months later I noticed that anyone searching for me had visibility of my G+ contacts (I wasn't signed in when I checked this) so I removed Google+ from my account.
Around the same time, the sign in for GMail, Blogger, YouTube and etc were unified, leaving users with the necessity to sign out and then sign in when switching site, or open the different sites in different browsers.
Recently, Google play was changed to only enable rating for accounts with Google+, forcing me to open yet another account, for rating apps.
If Google would let me choose which sites to log into for which accounts and let me log in to those accounts simultaneously (there was such a trial with limited site-support a while back) and would do more to protect my privacy by default, I would remain a happy user.