My article on  XML.COM “Revving the XSLT 1.0 Engines: Are they all the same?”  shows that XSLT engines vary dramatically in their performance. This has a direct impact on how to get the best performance for Schematron systems using the most common XSLT implementations.

Michael Kay, a vendor of one of the engines benchmarks, made some (nice) comments on the XML-DEV mail list.