Google Babble would have been exciting a few years ago. Right now, however, I'm already on iMessage/WeChat/Skype/FB Chat/Whatsapp, which is too much, really.
Since I don't already use any of Google's chat platforms, I'm going to avoid Babble. In fact, I'm kind of hoping it fails to gain traction. I'd hate to be 'forced' to use it in the future.
I suspect I'm no the only one thinking this.