The down votes may be a result of people detecting loaded questions, but in the event that they are not, here's my response:
> Is Ember.js actually worth learning? What's the point of my learning yetAnother.js?
You're a Java developer, so it may be harder for you to understand the productivity boon that frameworks like Ember.js and Angular.js provide than it is for people who have been dealing with jQuery spaghetti code on client-side javascript apps that have become increasingly more complex as browser javascript engines have become more capable. Ember.js, Angular.js, and other frameworks that offer two-way data binding are great because they take care of the dom manipulation details developers have typically had to manage by hand in the past. It frees people up to worry more about the business logic of their javascript apps. So if you're a javascript developer sick of writing boilerplate DOM manipulation code, Ember.js is definitely worth learning. I'm partial to Angular.js because it was built with testability in mind.
> Will it make me a better programmer (like learning Haskell will)?
Probably not, but it will make you a more productive programmer.
> Will it enable me to get a pay rise from my current £480 per day contracting fees?
If you're writing Java on your main contract, probably not. This is a bizarre question anyways and probably the source of your down-votes. I personally don't look at learning a new library or language in terms of how much extra money it will make me, but instead look at how much more productive it will make me as a programmer.
> Is there a more diverse and active job market than there is around my current main language (Java)?
I don't know much about the Java market, but I think it's safe to say that knowing Javascript cold and keeping up with the trends in that world will make you pretty darn employable these days.
Keep in mind that Ember.js and other frameworks like it are really only valuable to people who are writing single page javascript applications. If you aren't, or you are against the idea of building single-page applications, then these frameworks won't really do much for you. Although, you can still get some value out of them.
> Keep in mind that Ember.js and other frameworks like it are really only valuable to people who are writing single page javascript applications. If you aren't, or you are against the idea of building single-page applications, then these frameworks won't really do much for you. Although, you can still get some value out of them.
This is fairly true of ember specifically, but much less so for some of the other frameworks. Backbone and Angular, in particular, are very well suited for building "islands of richness" in otherwise traditional sites. Even if you're doing something relatively simple, like a form with live validations and inline error messages, you're going to have an easier time writing it with something to handle the DOM manipulation for you.
If you're wanting to get into frontend JS, start with Backbone. It's much less powerful than the other frameworks, but is by far the easiest to grok, and having it under your belt will give you enough tools to start moving larger and larger chunks of functionality into the browser. Come back to Ember once you outgrow that.
> Is Ember.js actually worth learning? What's the point of my learning yetAnother.js?
You're a Java developer, so it may be harder for you to understand the productivity boon that frameworks like Ember.js and Angular.js provide than it is for people who have been dealing with jQuery spaghetti code on client-side javascript apps that have become increasingly more complex as browser javascript engines have become more capable. Ember.js, Angular.js, and other frameworks that offer two-way data binding are great because they take care of the dom manipulation details developers have typically had to manage by hand in the past. It frees people up to worry more about the business logic of their javascript apps. So if you're a javascript developer sick of writing boilerplate DOM manipulation code, Ember.js is definitely worth learning. I'm partial to Angular.js because it was built with testability in mind.
> Will it make me a better programmer (like learning Haskell will)?
Probably not, but it will make you a more productive programmer.
> Will it enable me to get a pay rise from my current £480 per day contracting fees?
If you're writing Java on your main contract, probably not. This is a bizarre question anyways and probably the source of your down-votes. I personally don't look at learning a new library or language in terms of how much extra money it will make me, but instead look at how much more productive it will make me as a programmer.
> Is there a more diverse and active job market than there is around my current main language (Java)?
I don't know much about the Java market, but I think it's safe to say that knowing Javascript cold and keeping up with the trends in that world will make you pretty darn employable these days.
Keep in mind that Ember.js and other frameworks like it are really only valuable to people who are writing single page javascript applications. If you aren't, or you are against the idea of building single-page applications, then these frameworks won't really do much for you. Although, you can still get some value out of them.