Jim Smith
Member
There is no doubt the Trio's have the potential to best the Duo's, but they require a HUGE room - at least 18 feet x 24 IMO and they require no less attention to amplification, cabling, sources, etc. But if you have all the pieces in place, I can easily see how they are some of the best sounding speakers in the world.
That being said, I don't feel like I'm giving up a lot with my Duo Mezzo XD's IN MY ROOM.
As the AG distributor from 1999 to 2005, as well as doing RoomPlay voicings, I have some experience setting up TRIOs, DUOs, & UNOs - combined, maybe 75-100 pairs or so...

While the TRIOS do exceptionally well in larger rooms, one of the best TRIO systems I ever voiced was in a dedicated room 19' x 14' x 10'. I've always thought that to some extent, the performance advantage was probably due to the horns' 'controlled dispersion'.
People came from all around to hear it and all (AFAIK) said/thought it was their best listening experience ever. For the most part, these folks were NOT hornlovers, in fact some were openly skeptical (however the absolute MOST skeptical were Klipsch owners)...
IMO, the best TRIO sound is with the tweeter on the inside anyway, which helps slightly with off-axis reflections. FWIW - I have had less good overall results with the slightly more expensive TRIO CLASSICO than with the standard TRIO.
The hurdle is usually getting whatever bass drivers you have to integrate - IMO more tricky in a smaller room.