Efficiency is the big advantage of horns. Distortion can be lower due to lower diaphragm excursion, but then reflections in the horn can mess things up. They are hard to get right. I'd like to hear those Avanteguard (sp?) Uno speakers, though, just to hear for myself. I heard the Klipschorns, and they had a sort of a shouty quality that I found fatiguing, although the midrange clarity was excellent. Bass was punchy but did not go low, and the speakers were placed in corners in a large room, as their design requires.
As far as 'T'ruth goes, this is just opinion. No claim of absolute truth was claimed or implied.
As an EE for 40+ years, I can and do handle the truth. If I didn't, I'd have been shown the door a long time ago.