If you already have the Mac, OS-X vs Linux is usually just a matter of personal preference.
Exactly. I bought my Mac back in 2011 because nothing came close to the battery life and those specs at that price while being slim enough to be able to fit in my bag every day. Now, Yosemite really does look like an awful OS upgrade, visuals aside, there are some seriously bad bugs, the new spotlight (desktop search) sends every query to Apple (no idea why) and Microsoft (for Bing) and the fact that most of the new features require a recent iPhone. I'm clinging on to OSX Mavericks for now, but I will move to Linux if the battery life is decent.