I'm going to assume that since you're reading this, you're a technophile and you're already in the Google+ beta. I'm not going to talk about why Google+ is good, or how google finally "got social right", or why I love it more than life itself or any such nonsense. I'm going to talk about facebook.
Please don't misunderstand the title, I think you should try google+ out. If you like it (I do) then great! keep using it to your hearts content.
It's still about search
I'm pretty sure the primary reason for google+ is the +1 button. All this +1 action is going to give Google's search team a HUGE dataset to mine; no more scraping twitter for "social data". Facebook talked about doing this years ago.
It's good to understand Google's motivation before we pass judgement.
Now about switching: don't.
Google is a very powerful company and they've (finally) created a good social network with some profound insights. One that I personally enjoy using more than facebook and twitter. Facebook is also a powerful company, let's not kid ourselves but they are *much* smaller than google.
If everyone switches away from facebook and uses google+ instead, what we will have is facebook again, except owned by google (remember myspace). That isn't great.
Remember when Firefox started getting traction and over time started getting slow and bloated? And then Google released their own web browser, and all of a sudden Firefox was getting HUGE speed improvements? Right now we have 4 browsers with significant marketshare (sorry opera) all competing to be fast. That was great.
Well right now facebook has lost focus. They're the biggest by a lot and, frankly, they've got a bad case of slow-and-bloated syndrome (and a case of doing evil as well, but the degree to which they are doing it on purpose has been debated).
I'd like to see facebook have a change of heart on their crazy policies, and I hope Google+ is the catalyst. But it'd be a day when google controls our search, email, phones, photos, AND social graph.
Let's keep the Social Web competitive: let's force them not to be evil (and I don't just mean Google).