I have built myself a complete speaker sytem (6 speakers) based on an Ed Frias design (ARdiy.com). To me they sound wonderful; but of course this is very subjective. I've gone on to build many more sets for friends and family that were very impressed with the sound. I've also built an Octagon Tempest 15" subwoofer to complete the ensemble. I enjoy woodworking so the cabinets were ventures into imagination. I created a few different designs; not the typical box style.
Is a project in diy worth it? For every yes you could probably get a no.