well a few of the Denver folks have heard both, but never with the same electronics in the same room. I hate to admit this but Pez had a killer set up with the 626 ribbons and tubes which sounded fantastic. His room and synergy with the speaker was spectacular. I own the Diluceo's and love the ribbons and eton combination. I would say the 626's are faster in the mids, have more bass, and when set up right, really get you into the music. The Diluceo's are not made to play as low, but give a slightly warmer midrange with a killer tweeter. They both need a sub. Wayne has the latest 626 which is about double the Diluceo price, so for the bucks, the Diluceo does great, but maybe cannot get as low. It's a little like tubes in that they both have a great sound, just different. I truly believe that the room and right electronics helps. Pez hit the nail with tubes and the 626, while I think the AVA Fet Valve combo helps the Diluceo stay quick and accurate, although I would love to hear them on some tube gear for grins.