The only difference between promises and observables are multiple-emission & cancelation, they shouldn't be any more complicated to use or test than promises. O

The only difference between promises and observables are multiple-emission & cancelation, they shouldn't be any more complicated to use or test than promises. Often I find the main complicated part is the source, everything else is just filter/map functions, sometimes to more streams. All of these individual units are more easily described/tested in comparison to the entire chain (and even then you are only caring about the ends of it).