Couldn't agree more, using the XML toolchain (via lxml in python) for a recent project and it couldn't have gone better - you can get really far quickly with XP

Couldn't agree more, using the XML toolchain (via lxml in python) for a recent project and it couldn't have gone better - you can get really far quickly with XPath, XSLT, and Relax-NG schemas to ensure correctness. Writing XSLT extensions in python in participate is really powerful.