The great thing about Google plus is perhaps the circles features which means unlike Facebook, all your contacts are not lumped together and there is a way to group friends and people based on themes. This makes life much easier for controlling privacy settings and ensuring that you communicate with whom you want, how you want.
Google plus also has some of the great features of twitter, namely the ability to follow someone without them needing to follow you back. So called aysmmetric following which deviates from the all in one Facebook way.
Facebook is typically a closed system. I.e. you communicate with people you already know. However Google plus let’s you communicate with people you discover easily rather than being closed.
I do think Google is not doing enough to promote the fact that the system is open and enables otherwise unknown people to communicate with each other. A recently incumbent system was called Quora and this has some of the features that G+ has replicated, which has immediately killed my usage of Quora. Now I get chat and discussion without the back biting.
Google + is truly innovative in that it integrates the features that users want to see. FB has not innovated to keep people like me using its offering and for that reason FB will fall into the sea of dispair as it continues to aggrevate is users by not letting them work their online social world the way the offline world works.