jQuery’s flexibility, in combination with its community, provides a robust solution when dealing with complex user interactions. Additionally, a plethora of plugins and scripts are available through the open source community. Almost everything you can think of has a solution ready to be plugged in.
jQuery provides its own official UI support through jQuery UI (http://jqueryui.com/). This user interface offers a multitude of tools, including themes, effects, interactions, and widgets. Since jQuery UI is based on jQuery it allows us to easily integrate into existing jQuery code. This is a big benefit because developers do not have to worry about the stability of the engine and UI separately.
jQuery prides itself on being fast and there has been much improvements since its 1.2 release. There are many different types of performance benchmarks and they can vary when dealing with the creation, selection, and visibility of DOM elements (What is DOM? – http://www.w3schools.com/HTMLDOM/default.asp).
Here are the nuts and bolts. Speed / validity selectors test for frameworks. - http://mootools.net/slickspeed/# // Yes I know it’s from mootools.
Plugins & Demos