Am I taking crazy pills, or are these two things pretty much identical?
Having spent significant time with both frameworks at this point I would say that they are not "pretty much identical". While they may both use the same graphical assets, the way that they go about getting there is very different and depending on your needs/development style you may find one preferable to the other.
GWT-EXT encapsulates Ext-JS by wrapping the Ext-JS framework which can lead to frustration when attempting to extend functionality because you don't have access to the implementation at a low enough level. However, if you understand Ext-JS and feel like editing the javascript, that's still an option.
EXT-GWT is not a javascript wrapper. As mentioned before, it uses the Ext-JS graphical assets and some of the API's are similar but it is a completely native GWT/Java implementation. This makes extending the functionality a lot easier. Of course, the choice is up to you.
http://roberthanson.blogspot.com/2008/04/gwt-ext-vs-ext-gwt.html
that should answer your question.
Quote:
"For us GWT developers there is a project that wraps the Ext-JS library for GWT, namely GWT-EXT (GWT before Ext). The initial release was in July of 2007, and since then it encapsulates most of the functionality of Ext-JS.
Now just yesterday something happened that could undermine this project. The same team that developed Ext-JS has now released an initial beta of Ext-GWT (Ext before GWT)."
来源：https://stackoverflow.com/questions/1161029/difference-between-gwt-ext-and-ext-gwt