Right now I've been researching trying to find good solid number's what people have accomplished on these two machines in battery performance. The air 11" however is seemingly getting 4.3 hours roughly so far and the 13" is around 5.5-6.5 hours (this one has more feedback atm). Can anyone post their new 2012 air usage and brightness levels? Especially with the 11" since the only remaining factor in my purchase now is if there's truly a 2 hour difference at this point. Disregarding apples posted battery usage. Do you believe there's really a huge difference. I'd really like to go 11" if it can compete with its counterpart.