I have been really unimpressed with the direction of Mac OS the last few releases. The desktop environment is attractive to look at, but I find it somewhat sluggish and moody (don't you show me that dreaded beachball!). 10.6 is the last release I really enjoyed. The next two have been disappointing. It's obvious that Mac OS is no longer Apple's priority.

I dual-booted Arch for a time on my Macbook and was just blown away at the difference in responsiveness. I also had the familiar ease of maintaining/installing/updating/changing my development tools instead of dealing with brew or Macports and XCode.

The thing that prevented me from running Linux on this MBP full time is the less-than-stellar Mac touchpad gesture support. I do think Mac OS nailed gestures and touchpad interaction.