I think that your data in Google+ will be (at least slightly) less locked-in than data you add to Facebook: http://www.google.com/takeout

I agree with you that Google is pretty good about letting you export data. I just exported my Picasa pictures a few days ago. I use POP3 to keep a local copy of GMail. I also periodically take a local snapshot of my Blogger based blog.markwatson.com.

All that said, I also used Facebook's export facility several weeks ago. It worked fine, but then I realized that I didn't care about backing up my Facebook data and deleted it :-)

Earlier this morning I sent a review of Google+ to my customers as a FYI. I made the same point that Scoble did: techies will like the fine grained control, most people will not care.

Of my friends, the list of people who have been somehow burned by misconfigured or misunderstood Facebook privacy settings is growing steadily.

In general, I'm bullish on G+. A reviewer linked here made the best viral case for it I've seen so far: He hadn't made a profile or put any information out there on G+ but his friends with Gmail accounts added him to their various circle's and he, even having not yet chosen to participate in G+, got a big red notification stream in the top-right corner of every other Google service he uses.

Being able to download a dump of your data is a very poor substitute to a real federated network.

One good thing about Google+ might be that I don’t see it getting private messaging that is not email. So at least the messaging will stay open and you won’t be stuck with inboxes that don’t work on your phone etc.

Right, I don't either yet. I've only just started with it but I see nothing in "circles" that is mind-blowing or amazing. I already heavily use Facebook's lists so this is not that much better/different.

I wouldn't be surprised to see Google set up federation, considering that Google Talk started out without federation and they were trying to get Wave to have federation.