I recently upgraded the search with Apache Solr. The search function itself is actually far from finished and since I wasn't deep indexing before I'm a little short of proper documents to index at the moment. The bottom line is: It's awesomeness and then some. And the best part about it. If you have it configured properly once it's pretty much a self employed document indexer. You attach the document to a page, blog or $_whatever and a bit later it's automagically indexed.