[Zope] ZCatalog capabilities

[nwingfield at che-llp.com]

I'm working on an enterprise document management system that needs highly
flexible metadata structures - based on dynamic, customizable document
types - and lightning fast queries on this metadata.  The idea is to use
the metadata associated with each document to dynamically generate flexible
navigation routes and search interfaces (think iTunes or iPod) for any
document type.  Question is:  is ZCatalog robust enough for this purpose or
will I be better served by a relational data model?  Up to this point, I
have relied on Zope's object database, but I'm afraid that ZCatalogs are
just not sophisticated enough to do the job.  I would appreciate input from
anyone with real world experience in ZCatalogs.