I'd be interested in experience, tips and comparisons, too!
Especially how GWT compares to extJS and jQuery in terms of performance, ease of use, customization (complex ui design and implementation), maintainability, tools, benefits overall.. was wondering for some time now but didn't get around to use GWT for some project, yet :(
I was writing a small hobby project (a web email frontend) and abandoned GWT for ExtJS. I got a lot more done with a lot less code. Personally, I find javascript a more powerful language than java for writing event driven applications.
The advantage of using java is access to libraries, but at the time most of the libraries I was interested in wouldn't compile into a GWT application.
Interestingly, a rather big/complex web ui was done in extJS and it looks like extJS will be abandoned for new projects, mainly due to: little control over generated html/css and big performance issues, not i18n support, no code splitting, no unit tests and some other problems that seem to be solved in GWT.
I, for one, am suspicious if GWT is really the better way, basically adding anotehr layer between browser and sourcecode. My feeling points me more in the direction of jQuery, which probably doesn't do all this out of the box but many of this from plugins.
Why not? If they paying you to train in it, there is nothing wrong with GWT. It might not be the best framework to do things in, or it might be, but the learning experience alone might be worth it. You can easily transfer those skills to Java Swing development and Adobe Flex.
