IntelliJ IDEA ultimate has OS Project License for For open source projects.
I don’t want to say: “IDEA better than Eclipse”, be easy!
But IDEA 10 has excellent bundled pack of “inspections”.
These “inspections” can make Vaadin code base better, safer, cleaner.
Please, ask about ONE license (as minimum) and run all sources through IDEA’s inspections.
IDEA code inspection short
bigger list
PS: They have free open source
Community Edition
CE is good enough for many developers.
Same apply to
YourKit
license information
AMAZING Java Profiler
With those “best in class” tools Vaadin will be better 
It would be even better if there would be a Vaadin plugin for it. If you agree, vote for the
Vaadin plugin feature ticket in the IntelliJ IDEA backlog
.
done.
But, nevertheless, ask a license, it is painful to see how you bother with eclipse
I gave it my vote, too. Since GlassFish is an open-source project, many of us on the GlassFish team have a license and use Idea (and, of course
NetBeans
!). It’s very simple to develop Vaadin apps this way (*), but a Vaadin-specific plugin would be even better.
(*) 1. Create Vaadin global library. 2. Create web app. 3. 1+2.
Cheers,
Bobby