I'm sure everyone is tired of hearing about Google Circles, but it's nice. You can find me on it here. Are invites still a thing? If so, just send me your email address. It's still early on and I have my complaints and suggestions but so far I'm finding it easier to manage than Facebook, where friend lists & groups are annoying. And it's so far been a lot more social than Twitter, I feel like I'm discovering interesting people on it and conversations are happening more. Some of that could be the novelty of the new platform but I feel like it promotes casual socializing in a way I haven't really felt since BBS's. Also the Google Hangout multi-video chat is fun.
The other point in Google's favor is that I don't trust Facebook and never have. Google has a good record of openness and being pro-web, whereas Facebook has been intent on creating a locked-in walled garden from early on. I believe my interests align more with Google than Facebook, but time will tell.