GWT on AppEngine (which it has great integration for) has a ten second startup time when not loaded, and on the free tier they unload it when not in use, so that's not the greatest.

I used GWT for a while and it would be great for enterprise and large teams. The static typing which I usually love/insist on though, does seem pretty cumbersome for something as simple as a web page. I've switched to scala play for the back end and lots of tiny angular 'apps' on the front, and it's so much faster to develop for.

you should try out closure. it has static typing and a really well developed and tested library alongside the fantasitc compiler.

a lot of people who i've spoken to have the same impression of GWT (that it's slow, and not "webby"). I suspect it's because it has the same UI library model as java Swing, and that has the reputation of being slow (thru no fault of java to be honest - its usually the programmers who made it slow, when it could've been fast).

http://www.google.com/fonts <-- loads fast for me. In fact, i think GWT apps can do loading in such an optimized way that hand coding js will only beat it if the programmer is very very careful about it.

(ps, i have no affiliation with google, i just don't like mistunderstood tech to suffer…)