Late last year, I sold my iPad I wasn't using much and replaced it with
a Macbook Air. After using the laptop on a couple of roadtrips and
during long and boring meetings downtown, I was really impressed with
its battery life. I was getting 10-11 hours on a charge, and even at
that point, the laptop was not entirely out of juice.

Couple of weeks ago, I installed the new Apple OS X Mavericks OS on the
laptop and noticed that I got two full workdays of use out of the
device...around 14 hours, and the Macbook Air was still running strong.

An article on ArsTechnica backs up this long battery life, among other
points about the newly released Mac OS:

http://arstechnica.com/apple/2013/10...ery-benchmarks

If you have to attend long meetings and use your laptop during them, you
might want to read the article.