Agreed. I'm building a GWT app right now. I know Java inside/out. I don't know all the browser quirks and JS very well. I could spend time to learn it, but

Agreed. I'm building a GWT app right now. I know Java inside/out. I don't know all the browser quirks and JS very well. I could spend time to learn it, but GWT seems to solve the problem for me so far. I have hit a few cross-browser issues with some CSS and Regex, but I was able to identify them and solve them fairly quickly. GWT may not be the solution for you if you aren't a Java guru, but if you are, it is a godsend if you need to develop ajax ria apps quickly and you don't want to learn (deal with) all the browser incompatibilities and js nuances.