Product review: Inside open source AJAX toolkits
Yahoo User Interface 2.5.0
Support: Extensive support from Yahoo in forums and well-executed examples
Nutshell: Extensively documented tools from a group devoted to good user interface design
Yahoo User Interface (YUI) is a good solution for everyone. The tools are well-tested and generally more robust than many of the independent tools, and they are available for the price of a BSD license. The user groups are sophisticated, and there are plenty of good examples, something that is often missing in other documentation.
The YUI examples clearly show a wide range of the possibilities in the code. Many of the libraries have plenty of undocumented hooks in odd places that can be found only by reading the code. Yahoo does a great job explaining how to use them. The rich text editor, something that's missing in many collections in part because of the excellent independent editors such as FCKeditor, comes with 14 different examples on how to add or limit features, change the appearance, or interact with a distant server that might want to mark up the editor contents. My favorite part is the Flickr integration, which lets you search for images inside Flickr using tags.
So what should you do? Which should you choose? In the short run, a simple solution is to look for the precise widget you need. Browse the lists. Try the demos. Then just pick the one that will work for what you need to do.
That will work for a fast answer to a boss that wants something pretty slick and quick. But it's worth considering a deeper investment. When you’re ready to commit, you’ll want to look for the style and approach of the programmers. Spend a few minutes with the examples. Read the documentation. Where do you feel the most comfortable? All of these packages will solve most of the same problems. Major differences or missing widgets are usually erased quickly because the developers borrow ideas and code from one another. Cool widgets are often duplicated by other projects. The secondary issues are more important in the longer run. It's as much a choice over style as substance.
Is that too much work? Oh, just close your eyes, push your finger toward the screen and choose the name that's closest to where your finger lands. They're all good.