I'm going to venture a guess that you're only going to get politically correct answers on a public forum like HN.
Something along the lines of:
"We're happy to have some competition! By the way, did you know that facebook has had something like circles since 2009? Go to preferences and blah blah blah to enable it!"
or
"G+ and facebook fall into different categories and, in some ways, compliment one another! We're happy for google in this, but don't think it will effect facebook."
maybe if they get bold
"We'll be happy to see what google comes up with! Of course facebook employees are encouraged to sign up for the service, if they can get invites! We've heard it's quite the contest to get them right now! The couple of people that have tried it around my office said it was a bit buggy, but it is a good start!"
Something along the lines of:
"We're happy to have some competition! By the way, did you know that facebook has had something like circles since 2009? Go to preferences and blah blah blah to enable it!"
or
"G+ and facebook fall into different categories and, in some ways, compliment one another! We're happy for google in this, but don't think it will effect facebook."
maybe if they get bold
"We'll be happy to see what google comes up with! Of course facebook employees are encouraged to sign up for the service, if they can get invites! We've heard it's quite the contest to get them right now! The couple of people that have tried it around my office said it was a bit buggy, but it is a good start!"
etc.