Servicemix & JBI

[John]

I'm new to Servicemix and ESB. I read some stuff, especially at Mule there
are always the hint that Servicemix is a JBI implenetation. And JBI means
that ALL messages first are converted in XML and after that the further
processing is done.
Converting all message to XML may be a performance impact.
Is this still true for (the OSGi based) Servicemix 4?