Ext Javascript Library

[meandjiggs]

Has anyone ever used ext? http://www.extjs.com

I've been using it for a while for personal sites ever since we started using it at the place I work. I'm fairly familiar with it, but I'm completely unfamiliar with any other javascript libraries, so I don't really know how it compares.

Personally, I love it. It makes it easy to make sites with a very dynamic feel (with their easy-to-use AJAX calls and pop-up-esque windows on pages).

Opinions?

[tesco]

Can't offer any opinions, but I know vbulletin is now using a js library from yahoo.
http://developer.yahoo.com/yui/

Anyway, whenever I create pages they're a part of vbulletin so I use vbulletin's built in js functions. PHP functions too.
I love this, so much better than having to write your own and whenever something is changed in vbulletin (security) it takes effect for my scripts as well.

[4play]

mootools might be worth a look at as well.

[shurato]

I've been using jquery for a while, and am a huge fan. However, if you're building Rich Internet Applications, then ext is probably your best bet. Well, there are a couple other really good ones, but they cost serious money.