ePub to MOBI conversion

At different times I've used kindlegen and calibre for ePub to MOBI conversion, with varying results, but I've never been 100% happy with the result from either.

Does anyone on the list have any suggestions as to which of these (or which alternative) is the best choice for conversion when the ePub was generated using the DocBook stylesheets?

Thanks,
Dick Hamilton
-------
XML Press
New from XML Press:
WIKI: Grow Your Own for Fun and Profit
http://xmlpress.net/publications/wiki-how-to-grow