Perhaps the winning feature is "Circles". Google have recognised that people have different social circles, and communicate differently with the members of each. I think that if you add a friend into a specific circle or circles, they'll only be able to see the other friends of yours within the same circle(s), so for example if you have 'work', 'friends' and 'family', your work colleagues don't get to see your family members or your friends; likewise your friends can't see your work colleagues - so the proverbial situation of the boss taking a dim view of the photos of over-exuberant birthday celebrations is less likely to occur. If the security is as good as it appears to be (only time will tell - and let's hope they don't do a FaceBook and continually introduce more "it's a really good idea to share everything with everyone!" features), then there's the possibility of a 'TopShelfers' circle...

Circles could also be a really good idea if they create an app platform - so app / game requests are only sent out to friends who also play the game, rather than cluttering up the news feeds of everyone who doesn't play the game. The Facebook equivalent is really time consuming and irritatingly annoying - click the padlock, select Customise from the list, go to the drop-down menu and select Specifc person, type the name of the friend list into the box, wait for FB to recognise it, click OK, and Send. Never mind it's easy to mis-aim and accidentally select a network to send the post to as well (thankfully, I've always noticed in time... so far). Grrr.