About a year ago, the folks at Sun Microsystems came up with a bunch of benchmarks that showed that XML parsing in Java was much faster than on the .NET Framework. On the XML team at Microsoft we took this as a challenge to do much better in the next version of the .NET Framework. To see how much we improved, you can check out A comparison of XML performance on .NET 2.0 Beta2, .NET 1.1, and Sun Java 1.5 Platforms which is available on MSDN.

In the three test cases, Java 1.5 XML APIs are faster than those in the .NET Framework v1.1 both of which are about half as fast as the XML APIs in .NET Framework v2.0. The source code for the various tests is available so individuals can confirm the results for themselves on their own configurations. 

A lot of the improvements in XML parsing on the .NET Framework are due to the excellent work of Helena Kupkova. She is also the author of the excellent XmlBookMarkReader. Great stuff.

For the XML web services geeks there is also a similar comparison of XML Web Services Performance for .NET 2.0 Beta2, .NET 1.1, Sun JWSDP 1.5 and IBM WebSphere 6.0.