I want to quit facebook, but not for Google. Facebook has a lot of faults, most notably privacy-related: they sell your personal data to third parties. They also have a second problem, which is shared with any other provider of a "free" service. They can terminate your account without warning for any perceived TOS violation. This means nursing mums or trans men who post too much nipple can wake up one morning to find they can't log in. The same thing has been happening lately to activists. Losing your login means losing your data.
If I found one day I'd been arbitrarily deleted from facebook, I would be seriously irritated. For all its faults, it's been useful in helping me keep in contact with my godmother, for promoting upcoming gigs and for essential goofing off. But a deleted facebook account is not the end of the world. Nothing terribly essential would be lost.
I do worry about arbitrary deletions after I was mysteriously banned from ebay. But I just don't have that much invested in facebook.
Google has also been known for mysterious and arbitrary deletions, often of activists. They purport to be politically neutral, which seems unlikely. In any case, they have no appeal process and no customer support, so terminated google accounts are very rarely reinstated. If Google takes a dim view of some exposed nipple or a political opinion or just gets its wires crossed, it may also delete an account without warning. The newly deleted person is not a customer. Google has no contractual responcibilities. And it's not just Google+ access that goes.
If I lose my google account, I lose my email, my contacts, my calendar, my rss reader and my blog. I have too many eggs in one "free" basket. I am increasingly of the opinion that paying for services is the way forward. "Free" accounts are selling my demographics, forcing me to look at adverts and have no legal responcibility to me or my data.
I don't want to go from one privacy-compromising arbitrarily-deleting social network to another. Google+ is not the solution to this problem, it's just another instance of it. Like the great MySpace migration of a few years back, this offers only new shiny bits and no progress on fundamental issues. If they actually wanted to not be evil, they would fund Diaspora and host a pod. Otherwise, this is just another walled garden.