What are they? I've been developing with the @ngrx suite, and it's been mostly pretty smooth, what more do you want? I would like to see a piece of documentation that lays out explicitly what happens when you pass around Observables. Hot ones, cold ones, when the auto-unsubscribe clicks in, whether

    this.property$ = some_observable();
    this.property$.subscribe(fn);

... will auto-unsubscribe (does it? who knows... try it?), what happens when you async pipe and its interaction with ChangeDetection...

definitely agreed! It's become one of the biggest "advocators", so to speak. But I think people will want to learn it as a default, async primitive in JS as promises now are. Not saying support from Angular and other projects and also companies doesn't help, since it makes it look less like a "scary, new thing", but I think more people should start to teach it's benefits to be frank and blunt about it ;)