YUI's worked pretty well for me. The documentation is decent, and the code seems to have good support from Yahoo.

We're using YUI too. Has worked well for us so far.

A vote for MooTools, although jQuery is very nice as well.

MooTools is the truth.

MooTools is a fantastic library, with very solid motion tweening and decent documentation/examples. jQuery is also a very solid library.

JQuery, but I haven't tried a big variety. Right now, I'm using Prototype because that's what Weblocks uses by default.

me too

Prototype plus YUI, looking at jQuery

Just curious, what sucks about Prototype? It basically fixes everything that's broken with Javascript, which is about all I want my framework to do.

Big fan of Mochikit. As a python programmer it's got some good pythonic interfaces but it doesn't trample on the elegance of Javascript.

Second that. Mochikit has been rock-solid and a breeze to use.

jQuery.

Prototype 1.6 has some nice new features, and mootools is cool, but jQuery definitely wins.

shouldn't the title read "whats your favorite ruby Javascript framework?"

I was hoping for info on dojo, etc....

I'm not sure I understand. Why can't you use Dojo with Ruby on Rails? You lose the built-in ruby wrapper functions, but they're not required.

JQuery, plus occasional YUI

prototype is fairly annoying. i use it daily but prefer moo and jquery.

jquery... hands down

prototype + ExtJS