From a UI standpoint, I agree. There’s nothing like the classic Mac interface and its associated Apple Human Interface Guidelines for GUI software. I love Jobs-era Mac OS X, but the classic Mac and its ecosystem of applications were something special.

However, when it comes to UX, stability is a major component, and this is where Mac OS X is vastly superior to cooperative multitasking, lack-of-memory-protection Mac OS 9 and below. I prefer the classic Mac UI, but Mac OS X had a better UX.