Do you have references for "nothing even approaches"? Specifically compared to Sphinx? The only comparisons I've found are showing sphinx coming ahead in many indexing/search cases (if only slightly). See my other comment on this thread with links to benchmarks where sphinx clearly "comes close". We did a good bit of research on this, so it does feel odd that you'd say "nothing even approaches".

It was also ridiculously easy to get Sphinx up and going. Lucene is a killer engine, no doubt, but Sphinx's ROI alone won us over.