I work in gwt everyday and there are lots of pluses to it such as the easy communication between the client and server and taking away a lot of the dom headaches. However, I have several issues with it. Compile time from java to javascript is very slow, simple app takes a few minutes to compile. You typically will work in a hosted mode browser so changes are on the fly, in many scenarios things work in the hosted mode browser, but fail inside a normal browser, regex and bigdecimal use are two such pain points.
A big issue that I have with it is that developers end up putting way too much business logic inside the gwt portion of an app, simply because its just java anyway, right? You can't really blame gwt for bad programming, however, because of the notion of its just java it easily allows developers to not think and just put business logic in the ui. If this was javascript developers would much rather do the more complicated business-y things on the server side (typically where it should belong), rather than in javascript because most people really dislike working in JS. I personally feel that its very difficult to build a gwt app while maintaining a clean well refactored codebase and doing TDD is also very difficult with the framework. I say difficult and not impossible, because I have done it in the past, but its not easy and really takes time and care. Again because its not easy to do these things developers tend to not do them, thus leading to messy, hard to change apps.
>simple app takes a few minutes to compile
>You typically will work in a hosted mode browser
I thought those issues are now thing of the past. At least that's what I saw in google i/o presentations.
For the other part it seems more like an issue with development approach and not GWT per se. I have only dabbled a bit with it and like it more than writing JS for full blown web apps.
Cappuccino intrigued me because of my background in desktop apps - albeit not Cocoa. There are many idioms I am used to, so I'll give it a spin.
A big issue that I have with it is that developers end up putting way too much business logic inside the gwt portion of an app, simply because its just java anyway, right? You can't really blame gwt for bad programming, however, because of the notion of its just java it easily allows developers to not think and just put business logic in the ui. If this was javascript developers would much rather do the more complicated business-y things on the server side (typically where it should belong), rather than in javascript because most people really dislike working in JS. I personally feel that its very difficult to build a gwt app while maintaining a clean well refactored codebase and doing TDD is also very difficult with the framework. I say difficult and not impossible, because I have done it in the past, but its not easy and really takes time and care. Again because its not easy to do these things developers tend to not do them, thus leading to messy, hard to change apps.