When we asked Rackspace what else we could do to speed up the performance of our server (our forum has 5.1m posts at present), they said our main bottleneck was the search facility. They suggested swapping from vBulletin to Sphinx, but the problem was that my technical knowledge doesn't extend as far as working out how to integrate the two. Thankfully Floren and his SearchLight product came to the rescue - here was an 'out of the box' solution that worked with the existing vBulletin product/plugin system. Combine this with Floren's friendly and dedicated support and you have a 'winning' (as Charlie Sheen would say!) combination.