I guess it doesn't matter much to me whether I use FB or G+ since I filter my posts BEFORE posting it. That seems to make more sense than to hope I only send a particular message to my "Wanna hear my drunken rant" circle and not my "Kiss up to my boss" circle. I also do not add people from work on FB or Google+. If it is truly a friend then maybe, but I see them at work, they don't need to see what I did on the weekend, and for the most part I don't care what they did. I would never add a boss or a subordinate and I do NOT list my place of employment by name, and I do not name co-workers in my posts. That is just begging for litigation. We fired a guy last week because of his Facebook posts, degrading co-workers and his bosses by name and copping to all kinds of things about work, naming names of both the company and specific employees. He posted that he was surprised he passed his drug screen. Also, I am not so narcissistic that I need any of my profiles to be public, so I just make it all private so only my friends can see it. This way I can easily say what I choose to, and keep in touch with my family and friends, without worry of offending anyone or someone snooping and getting information out of my profile. Circles or Friends Lists don't do anything to help me with that, I filter it myself.
The biggest problem with all this is privacy and protection of identity and I protect that by controlling who I add and what I post...period.
The principle to keep in mind is that once something is in the internet it will always be cached somewhere on some server. Once it has been posted it can never be undone. The privacy settings are well and good but they don't stop anyone who has some technical skill or is determined. For example say your background is being checked as part of the interview process. The private investigator isn't going be worried about your circles on Google+ or your privacy settings on Facebook. They are going to find all the information that you have put online.