CPython vs. Jython for Web applications?

[John E. Barham]

Good day,

I'm considering writing a fairly sizable Web app in Python and would
appreciate advice on whether to use CPython or Jython.  My main
motivation for considering Jython is "native" access to Java's more
mature XML libraries for XSLT (e.g., Saxon) and SVG (e.g., Apache's
Batik).

The constraints are:
 - data to be stored in a relational database, preferably open-source
 - app must run on both Win32 and some free Unix, preferably FreeBSD
 - interface will be generated using XSLT
 - app must run in Apache using some form of embedding (i.e.,
out-of-process overhead of classic CGI is unacceptable)

I'm more interested in ease of development than optimal performance
but performance still matters...

Some questions:
  Has anyone written a sizable Web app in Jython?
  Are there real-world benchmarks comparing, say, Jython & Saxon vs.
CPython & Pyana/Xalan?
  How do Jython servlets compare to using something like mod_python in
terms of speed and ease of use and scalability?
  How painful is it to do Jython database access vs. the standard
Python DBI?

FWIW, I have a lot of experience with C++, CPython and XSLT but just
an undergrad course's worth in Java.

I appreciate that Jython's performance is dependent on the JVM, so
advice would be appreciated there as well, especially regarding the
performance of JVMs for the free Unices.

Thanks in advance.

  John