Solid machinery, has a genuine Unix shell ("Unix-y"? More Unix than most Linux distros), if it runs on Linux there's probably a port for Mac OS, sound works out-of-the-box (I know, cheap shot), and I get my work done with a minimum of fuss when I plug in hardware.

Personally, it's the only choice if I'm going to work on iOS, and conveniently I can do Android work as well. Basically (and again, personally) it does everything a Linux box is going to do, plus iOS dev.