[gregnbanks]

Sphinx also had a bunch of really bad bugs around server startup and shutdown, and some ugly code. I ended re-writing some of their pthreads code and submitting patches, I have no idea if they ever used them or not because their development tree is internal and not visible outside their company.

Solr (well, Lucene) has awesome natural language stemming abilities, many more languages supported than Xapian. In particular it's much smarter than Xapian about Chinese. But a) the memory requirement makes running multiple shards on the same machine hard, and b) nobody in the company wanted to learn how to handle Java operationally.

EDIT: since 2012 Sphinx appear to have made a public mirror of their internal tree at https://code.google.com/p/sphinxsearch/source/checkout