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…)