Battery Is Good!
I received my 1.2GHz, 512GB MacBook more than a week ago and I can't complain about the battery life. I take mine to work and leave the charger there because I only need to charge it for a little bit each day. I haven't done an extensive battery test but the eye test gives me 8.5-9 hours easily even when working on light CAD files, browsing, messaging, and email. Keep in mind that time is relative and I'm coming from the 2012 15 inch MacBook Pro Retina. That battery life is terrible compared to this MacBook.