I was hoping that 4.1 would be more stable compared to 3.4. There are a lot of layout issues. I think Sencha should focus on that instead of performance.
Grid and (tab)panel layout do strange things. I now tested 4.07, 4.1 is not working in my app. Performance is not that good but will do, but get it stable please!
A stable program is better then a fast unstable program. And please throw out that MVC Loader stuff. I want all my js files loaded at once. It is really impossible to put my 3.4 in that MVC thing, my app is to big to handle it in the way the architecture of Ext 4 wants me to do.