From the post:
<oXygen/> XML Editor 16 increases your productivity for XSLT development with the addition of Quick Fixes and improvements to refactoring actions. Saxon-CE specific extensions are supported and you can apply now XPath queries on multiple files.
If you use Ant to orchestrate build processes then <oXygen/> will support you with a powerful Ant editor featuring validation, content completion, outline view, syntax highlight and search and refactoring actions.
Working with conditional content is a lot easier now as you can set different colors and styles for each condition or focus exclusively on a specific deliverable by hiding all excluded content. You can modify DITA and DocBook tables easily using the new table properties action.
You can customize the style of the <oXygen/> WebHelp output to look exactly as you want using the new WebHelp skin builder.
As usual, the new version includes many component updates and new API functionality.
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Too many changes and new features to list!
Not cheap and has a learning curve but if you are looking for a top end XML editor, you need look no further.