I'll also cast a vote for YUI. Caveat - I'm a product manager and not a developer, and the eng team chose YUI on it's own. It really worked out well for the pro

I'll also cast a vote for YUI. Caveat - I'm a product manager and not a developer, and the eng team chose YUI on it's own. It really worked out well for the product - we were able to put out some really impressive features using YUI data tables and some light use of other things as well. Basically, a lot of business app development is taking data from the database and making a table from which users can edit info or add new rows. All of the stuff that you need for that is in YUI - inline cell editing, tabs, hiding columns and picking them, and formatting data. The performance is excellent as well - the data table performed really well even if there were hundreds of rows.