I prefer jQuery. Mainly because for what I do with javascript, it feels a lot more "declarative" (best word I can think of at the moment) than Prototype.
> which JavaScript/Ajax framework is the best<p>Well, personally I do plenty of Javascript (DOM manipulations, in-page logic and interactions...) but barely any "Ajax", and prefer jQuery. But isn't that in the end always the answer: "which one do <i>you</i> prefer"?