Now when resources change, auto-build occurs in the background, allowing you to continue working. If you modify a file that affects the background auto-build in progress, the build will be automatically interrupted and restarted. Build progress is shown in the status line, or in the Progress View.
(Naturally, background auto-builds do not occur if you have disabled auto-build via the Workbench preference page.)
Finally! This should be worth the upgrade! This release has some other need improvements like better CVS support, refactoring and Java compiler support to flag problems. Make sure you check out the new features.