Flex (for better or worse) is still widely used in the financial space.
We started using the full google closure stack a couple of years ago and I am happy about that decision everyday.
Frankly, it soured me on the whole third-party framework idea, seeing how it was impossible to predict which one will retain support over the years.
Longer term maintenance is a pleasure with closure, adding new features a breeze, there are tons of exceptionally well tested components and I cannot stress enough how wonderful deep static analysis and dead code elimination is.
Angular is basically MVVM for the web, which is awesome because MVVM is awesome.
Closure is OOP and "lets move heaven and earth to pretend we are still coding java, but with a weird syntax and lambda functions". It appeals to different needs.