I have been using Oxygen for a year or so and I am more than happy with it. It is very flexible and extensible. It comes with several xslt transformers (saxon, xalan, msxml), so the transformation of EAD to HTML is easy.
I was working with NoteTab, XMLSpy, and xMetal, but I found Oxygen the best considering price, functionality, and usability.
Stanislav Pejsa | Quality Control and Metadata Librarian | Gruss Lipper Digital Laboratory | The Center for Jewish History | 15 W. 16 Street | New York, NY 10011 | [log in to unmask] | (917) 606-8213