Just two months after the 1.0 release, Dart 1.1 is available with better performance, more features, and improved tools.

Seth Ladd's post announcing the new release of Dart 1.1 on Dart News & Updates has the headline Dart 1.1 features up to 25% faster Javascript and presents output from a benchmarking program to demonstrate it:

(click chart to enlarge)

Ladd comments:

Dart’s Javascript output continues to shine. Performance on the
Richards benchmark is 25% better than the first release, making
runtime comparable to the original JavaScript. Performance of the
newest benchmark, FluidMotion, has doubled since November. Dart2js now generates Javascript that performs as well as, if not better than, the idiomatic Javascript equivalent.

Ladd notes that the release  provides a number of enhancements for server-side Dart, including support for large files, file copying, process signal handlers, and terminal information. There is also new support for the  User Datagram Protocol (UDP), which is intended to allow developers to write more efficient media streaming apps; and documentation to support command-line and server-side Dart applications.

The updates to the Dart Editor include improved debugging, code implementation and more descriptive tooltips. Overall performance of the editor and the analyzer has also improved.