For as long as I’ve been involved in UI design, I have considered the Apple Human Interface Guidelines to be the gold-standard of User Experience guidelines. They are available on Apple’s developer website, and are well-worth reading, regardless of your target development platform.
Of course, the Apple guidelines aren’t perfect; it’s simply not possible. Additionally, the recent willfull deviations Apple has made in their applications has raised the hackles of many in the Mac development community.
My take on it is that Apple has every right to innovate on their platform, and this will eventually lead to some inconsistencies in their UI guidelines. That said, rational explanations on why they’ve deviated, and further information on how 3rd party Mac developers can stay in sync with the current round of guidelines would be extremely valuable. Of course, these new guidelines would be eclipsed so quickly that it would only serve to frustrate developers, but such is life:
This guy trashes the HIG the way Johnny Depp trashes a hotel room. He even sports a custom radius on his window corners. No other window on the system has a shape like this. It’s wild. Just wait until the HIG zealots get a load of this guy.