BaseX is actively developed (6.0 came out about two weeks ago), but I understand your concern.  It seems like they are moving towards building more of a community around it (mailing lists and such), but yes, the core is pretty much the university team. 

eXist has more plug-ins and specialty features than BaseX. BaseX has XQuery full text search and much much faster querying speed.

As far as putting your eggs in a basket, I'm pretty sure that if you're looking to base your project around XML databases, you're already putting your eggs in a basket of some form...

-Sean

On Jan 19, 2010, at 1:00 PM, Godmar Back wrote:

> On Tue, Jan 19, 2010 at 10:09 AM, Sean Hannan <[log in to unmask]> wrote:
>> I've had the best experience (query speed, primarily) with BaseX.  This was primarily for large XML document processing, so I'm not sure how much it will satisfy your transactional needs.
>> 
>> I was initially using eXist, and then switched over to BaseX because the speed gains were very noticeable.
>> 
> 
> What about the relative maturity/functionality of eXist vs BaseX? I'm
> a bit skeptical to put my eggs in a University project basket not
> backed by a continuous revenue stream (... did I just say that out
> loud?)
> 
> - Godmar