I've been developing a custom search for my site using lucene. I've found lucene fast and very flexible. I have a small site so the flexibility is more important to me than the speed.

I messed around with sphinx a bit. There were a couple of restrictions on how the DB tables were organized that would have made it a pain for me to use (like all primary keys had to be ints). But it was very fast for me. But again, I have a very small site, so YMMV.

When you say "isn't good enough" do you mean with respect to speed or something else?

Yeah, I agree with you that a lot of search implementations tend to be too literal.

Lucene is very nice in that respect. If you have a domain specific site, you can plug in your own aliases for various terms, as well as different stemming engines.

I'm using Roller for my blog engine, and since they're both written in java, it's a nice fit for me.