I must state that I don't see a downside to choosing Java. Recent versions load fast, even as a browser applets. I've been a Java-hater for quite some time, but with the recent 'opening' of Java I think it might get a second try in the web-app department. I don't know the numbers on Java penetration (maybe someone could visualize it! :) but I'd that it's still in the +85 percentile, good enough for non-critical websites like this one.