At Open Plans we've been thinking some about Javascript WYSIWYG HTML editors lately. Kupu is the incumbent editor because it's the default in Plone, but we needed to make a more conscious decision since it's pretty key to the basic functionality of the site. I worked up some criteria for evaluation and started the evaluation; mostly what the communities and code bases look like. We're evaluating Kupu, Xinha, TinyMCE, Dojo, and Wikiwyg. I left out FCKEditor because I just didn't feel like testing everything, and something has always seemed odd about that product to me, and it doesn't seem to offer something distinctly different from TinyMCE and Xinha. If I'm wrong to leave it out, please correct me in the comments...

This first round will probably knock out Dojo and Wikiwyg. The Rich Text editor in Dojo seems peripheral to the product and project, and the larger framework is just too hard for us to track or deal with. Wikiwyg is really focused on how to provide WYSIWYG editing to people using Wiki markup; we're using HTML, and using Wiki markup just opens up a whole can of worms to ultimately create something less general and powerful than the full expressive power of HTML.

If anyone has opinions I'd love to hear them. Especially fuzzy opinions like "X just felt better to me than Y" -- it's hard to really know how good these feel without spending some time seriously editing using each editor. I guess we'll have to figure out some way to do that, but unfortunately it's not trivial to set up each one.