> Are the Apple-owned app windows inconsistent too? I see some inconsistencies but it's generally 3rd party apps mixed with Apple's apps.

Does it matter if it's 3rd party apps or not? Wasn't a huge part of the sell with Apple's own GUI toolkits that all native apps work uniquely, but look familiar and like part of one and the same? The consistency and "all apps look and work great" I seem to recall being one of the "features" people used to tout about OSX.

FWIW; TFA compares the border radius of TextEdit and Calculator, both two Apple apps, built-in nonetheless.