fluent in 3 languages ... and CSS ... you got it!

The reason I settled on the yahoo offering is, many of the other ones (like scriptaculous) have very large footprints. YUI is more modular. Plus they offer compressed Libs and even have a JAVA compressor. Development seems to be ongoing, Docs are great, and support in the forums is excellent.

When scriptaculous went to 300K for the lib and I started getting timeouts on my users I went to AJS. Not bad, but docs were scanty, few bugs, no support, and it was time to change yet again.