Santiago has been working for a while on performance issues around Web Services and XML. He is a member of the original team that worked
on the Fast Infoset standard and implementation (see the fi project), and is now contributing to the improvements to the iStack (JAXB 2.0 and JAX-WS 2.0) implementation in GlassFish. In his
he discusses the performance of JAXB vs DOM using results from
the japex framework.