1.- It is better than JavaScript, is like using C# with a litle mix of Java.
2.- It comes with its own libraries, no more underscore.js or other patch libraries that JS needs, it is already in the toolkit.
3.- It comes with the Dart Editor, where you can debug your code easily, for scalable projects I find this to be invaluable.
4.- It will run in all your browsers, because it will export your code to JavaScript, but not only export it, it will optimize it and will run really fast.
5.- The pub library, go to pub.dartlang.org and you will find lots of packages that you can install and use, like a bootjack, a bootstrap port in Dart.
There are prolly many more, but these are the ones that come to my head right now.
But it also has its own problems like:
1.- No Dart support for Chrome yet and we don't know if there will ever be at this point.
2.- The generated JavaScript will be huge, and I mean huge, mine is like 460k per file and I'm not using polymer, when I used polymer the generated JavaScript was over one megabyte, just insane in the cloud.
3.- Get use to regressions, with every point update I've have issues, I upgraded from 1.4 to 1.5 two days ago, now my code is broken It runs, but it will for example run futures twice, So I went back to 1.4 for now, I had some other issues with UTF when migrating from 1.3 to 1.4 so, get use to.
4.- They are slow fixing bugs, looks like polymer and speed are their priorities, but when you need something trivial that other languajes have had for years and you report a bug it will get ignored, I've waited for 18 months and my open bugs are not fixed yet.
I would say that Dart is nice and you should give it a chance.
If you include all of your 'standard' libraries in a JS app, it can be pretty big. I basically pull everything together for an Ember app I work on, and all-told it's ~3MB prior to minification. Minification takes it down to ~1.5MB, and Gzip-compression on the server takes it sub-1MB (can't recall the number off-hand). It's not that far off from what you might have in a JS-heavy app.
[disclaimer: I work for the Dart team.]
https://www.dartlang.org/polymer-dart/
We also have Dart packages for the Polymer project's core-elements and paper-elements (Material Design, nee Quantum Paper) that were announced at I/O.
http://pub.dartlang.org/packages/paper_elements
Web components and Dart is a really powerful combination for apps.
[1] https://www.blossom.io/ [2] http://www.ramen.io/post/46936028144/we-are-switching-to-dar...
We're super happy with Dart & really excited about polymer. Love the language & platform in general.
We'll put out some essays, code snippets & lessons learned in the next few days :)
Stay tuned.
And how are you finding Dart to be verbose? In my experience it can be more concise than JS because of short lambdas, no function keyword, method cascades, real classes, the fluent Iterable and Stream interfaces.
On the other hand, I see some Dart programmers use a lot of classes and type all their variables. I'm curious what ended up being verbose for you.