Sphinx is an excellent option for full-text search. The post didn't go into depth on our particular use case, but this full-text indexing is just a small part of a larger filtering system. Having the index in Redis meant that we could execute the entirety of the query (which may factor in users, tags, modification dates etc) in Redis via union/inter/diff operations.

Could we have learnt and used another technology? Sure, and we may still do so. For now this solution works well for us.

Should other people use this technique? Like always, it depends on the situation.