Hi Glai,
I've owned Duos for the last four years and I currently own Avantgarde's new Meta Primos. Prior to owning the Duos I owned the fantastic sounding Hales Transcendence 8 loudspeaker. I have three friends who own Duos, two friends who own Unos, and one friend who owns Solos. I've also listened to three different Trio set-ups. The strengths of the Avantgarde line of loudspeakers are: life-like dynamics, transparency, uncolored, speed, focus, dynamic contrast, dynamic shading, imaging, they bring out all the raw emotion in recordings. The weaknesses are: not easy to set-up, very easy to make them sound bad, very picky about amplification (very revealing of amplifier noise), you almost have to use tube amplification, and bass integration with horns. The Duos better the Unos in the midrange. The Duo horn goes down 170 hz where the Unos midrange goes down to 220 hz. IMHO the Duos are slightly warmer/richer sounding compared to the Unos. If you liked the Duos with a Cary 805C, then you'll love listening to them with a good 45, 2A3, PX25 or 300B SET amplifier. Avantgarde is one of those products that some very vocal people love to hate. Most of it comes from the Do it Yourself (DIY)community and some of it comes from resentment of the high price tag. They are not perfect but I like them. Take care!