The cross-browser promise of GWT will only get you something that runs in ie6. It might never give you something that performs well. No layer of abstraction w

The cross-browser promise of GWT will only get you something that runs in ie6. It might never give you something that performs well. No layer of abstraction will ever cover up the fact that you have the world's worst garbage collection algorithm coupled with the world's slowest javascript runtime. At best, it can only make the semantics of your code the same across the various browsers. It's the difference between getting an obese person to walk 26 miles when what you want is for them to run a marathon. Also, at its core GWT is just the compiler, and you can (if you desire) choose to ignore the cross-browser abstractions and work at a lower level if you want the best possible performance. For example, a mobile safari app written in GWT (one that needs to fit inside a very small browser cache) might avoid using GWT Widgets to keep the resulting javascript as small as possible. It could be that the Wave developers took that route.