For all Urs' bad points, the point about internal vs external is incredibly true. XAML was a slow, painful mess in Windows 8 because all of the internal UI was

For all Urs' bad points, the point about internal vs external is incredibly true. XAML was a slow, painful mess in Windows 8 because all of the internal UI was largely developed in a parallel private internal framework. Once the internal shell UI started being built with the exact same frameworks and tools as public customers had to use, there was suddenly a bunch more pressure and resources dedicated to making them suck less, and the ecosystem as a whole was better for it.