Mootools, Scriptaculous, Prototype, YUI or JQuery?

[eluser]Edemilson Lima[/eluser]
I liked very much the ability of jQuery to traverse the HTML based on its CSS classes. This allows me to have a much better control of my web page.

About the size, jQuery is smaller than Prototype and also have many effects. To achieve the same with Prototype you must use Scriptaculous too. Yes, you can use GZip, but it is not a standard proceeding. Not all providers offer this.

Small footprint is good for faster loads, but jQuery also have a small and optimized code, so the browsers uses less CPU cycles to achieve the same results. This maybe not noticeable on faster computers, but can make a huge difference in old machines.

I like that YUI have some useful tools like auto suggestion, HTML editor, color picker, date/time picker, etc, already built-in, but people say it is too bloated. By its turn, jQuery have a nice repository of plugins, where you can pick up any tool you need. Moreover, this repository is also growing more and more.