Mavericks battery life improvements...
So that was one of the big touting features of Mavericks was the fact that with system optimizations, they were going to be able to use hardware more optimally, and thus, give all users switching to Mavericks better battery life. I was skeptical...and wondered if Apple could do it with a software update (or, more fairly put, major OS update)...why couldn't a 3rd party developer do the same thing (and why hadn't they to this point).
I decided today would be a good test. I normally get a good 4.5-5 hours out of my battery on 100% charge with moderate usage, and about 4 hours consistently under heavy usage (movies, internet, emailing, etc). Today, under heavy usage, I'm at 5 hours of usage (5:30am-10:30) with approximately 45min. of life left, putting me at around 6 hours life total (depending on my further usage).
That is really quite awesome. It seems Apple's estimates were not just hot air to get you to upgrade, the system is, in fact, significantly more optimized. I can't imagine what people will be getting on the Airs (given their already stellar battery life).