Why choose Dart?

There are five main environments where you can run Dart:

• Dart compiled to JavaScript in practically any modern browser. The Dart SDK is shipped with Dart to a JavaScript compiler called dart2js, which takes your Dart code and compiles it into vanilla JavaScript. Right now, this is the most typical use case in a production environment.
• The Dartium web browser comes out of the box with the Dart SDK. It's a modified version of Chromium (basically, an open sourced Chrome) that contains Dart VM along with JavaScript V8. We'll use Dartium for easy debugging and to run the Dart code without compiling it to JavaScript.
• The standalone Dart VM allows you to run Dart code as a CLI script just like any other scripting language. The dart2js compiler itself is written in Dart.
• Google Cloud Platform, since the introduction of Google's Managed VMs in November 2014, it also supports a hosting environment for server-side code written in Dart.
• Fletch is an experimental highly concurrent Dart runtime, which will be able to run on both desktop and mobile platforms. It is scheduled for its official release at the end of 2015.

Dart VM is able to run your Dart code significantly more effectively than JavaScript V8. You can see current benchmarks at www.dartlang.org/performance/. Note that the dart2js compiler is doing pretty good even though the compilation process brings some additional overhead.

After the first public release of Dart, Google claimed they were planning to implement Dart VM right into Chrome as an alternative to JavaScript. However, on March 25, 2015, the Dart team released a blog post stating that after collecting reactions from their internal teams, they've decided to stop efforts to integrate Dart VM with Chrome and rather focus on improving integration with JavaScript.