I haven't actually tried using both RxJS and Knockout together, but it's something I'm thinking about doing. It might seem strange to merge these two different approaches, but I'm a fan of MVVM (which KO espouses) and of KO's templating and component functionality. To get it working, the callback in an RxJS subscribe method would set a KO observable, which would then be bound to the view.

IIRC KO's author is familiar with RxJS; he made KO and reduced the concepts to observables (of which there are similar objects in RxJS) and computed properties as he felt it was more straightforward for the typical dev in not requiring one to make the paradigm shift to stream composition.

I think that KO, especially when using components for encapsulation and reuse, can be a very powerful tool. But once I started combining KO with Bluebird for promise combinators, I started to understand the benefits of the stream-based approach better (in RxJS promises are just another source of events, which is a very powerful tool that I should have mentioned in the original post).