I smell selection bias. Have you never visited HuffingtonPost, Gizmodo, or PandyDaily and looked at the network tab? Javascript does not automatically make people produce fast and snappy sites. That is based on experience, regardless of language. There are tons of websites that make a boatload of script include requests and image requests because the developers haven't learned about UglifyJS or Closure Compiler yet, or don't know about CSS spriting. Take a look at flights.google.com, it is a GWT app of non-trivial functionality that loads faster than most comparable sites (<2 secs) and makes far fewer requests. Another good one is the SpeedTracer app for Chrome (it runs as an extension). It has a very very nice UI, better than Firefox and WebKit WebInspector, and it's a GWT app.

Anyway, why do you think Google does all of their hand-coded JS apps with Closure and the Closure Compiler? It's not because JS 'out of the box' is conducive to producing best-of-breed apps. Web programming requires a large amount of on-the-job acquired knowledge. How many people are aware of CSS selector performance, or the performance effect of reading element.offsetWidth?

GWT doesn't prevent you from shooting yourself in the foot, just like any other language. Producing optimal apps in any language requires experience in that language. Knowing how to arrange non-blocking behavior in script inclusion, or batching requests, is something that comes with experience. I wish I could produce a boilerplate framework that could make amateurs produce absolutely optimal apps out of the box, but that would trade off	a lot of freedom.

However, GWT does offer tools to reduce your HTTP requests, and it's been doing this for years before they became common place in JS. For example, GWT has had automatic CSS spriting and image optimization since 2007. It's been doing CSS optimization nearly as long. GWT 'perfect caching' has been in from the beginning, which guarantees that most of the time, the app is loaded via a single HTTP request to a small 2k bootstrap file. In fact, it's possible to load your initial page:	html, js, css, images in just 1-2 requests if you desire. Obviously, there are tradeoffs there too, that are platform and app-dependent.

There certainly are some APIs in the GWT SDK that can produce bloat if you use them, and that is wholly dependent on your preference. The GWT RPC system, for example, is great	for internal apps, because it makes server communication trivial, but GWT also includes regular JSON/JSONP/XHR support. You can choose to use Widgets, or you can built your UI with HTML templates and CSS, just like you might do with Handlebars in JS.

I guess my point is this: I don't deny that an amateur Java programmer could take GWT and unknowingly compile a huge amount of junk into their app or make an insane number of HTTP requests. I just don't think producing apps with terrible startup latency is GWT specific, and I've seen enough websites in JS that are absolutely terrible to know that the way you get an optimal UI is by hiring good engineers with web experience, not by language choice.

And on that note, it's quite easy to get upvotes IMHO when you start a language	war, because people are	so opinionated on one side or another about it. My own personal opinion is that you should use the tools you feel most productive in, period, and if that's JS, or GWT, or CoffeeScript,	or Objective-J,	than more power to you.