Gday Mark,
I am from down under in Sydney, Australia so it might seem strange to get a response from the other side of the globe! I have been living with the Crescendos for over a year now and am one happy camper. As you can imagine the Australian market offers limited choices of speakers but we do have exposure to some fine offerings. I spent the good part of 6 months auditioning different floorstanders from B&W, Sonus Faber, Dynaudio, ATC, Focal to name a few. I just felt they all sounded similar in the $15K to $20K price range. Nothing really stood out for me. When I read that one sole chap was importing Acoustic Zen in small quantities I made the effort to have a listen to the Crescendos in his own house. The speakers are larger than most competitors but not overly so. The gentle tapering of the cabinet lends the speaker a graceful presence. I am certain when Rob Lee was designing the Crescendo its ultimate size played a big part in its end result sound. They just disappear within the huge soundstage they produce. I found absolutely zero listener fatigue as the sound is not at all 'pushed' towards you like some speakers do. A slightly laid back sound means the speaker, despite its size seems to work in smaller rooms. My room is only 12' x 15' and using appropriate room conditioning such as bass traps in the corners and a few acoustic panels here and there I have simply magical music in my room.
On the note of the PSB Synchrony One, I had the pleasure of a home demo at a friend's place and really it is no competition to the Acoustic Zen Crescendos to my ears and my friend's. The PSB Sync One is a fine speaker but I felt it nothing out of the ordinary for its asking price. The extra spent is a 'no brainer' as you guys like to put it! At the risk of upsetting PSB owners the Sync One is a fantastic speaker beating many similar offerings from B&W, Focal etc but I just felt was not in the ball park of the Crescendos. And it shouldn't be as it is significantly cheaper too!
Hope my thoughts were of some help.
Cheers,
Victor.
ps I believe there are only a handful of the Acoustic Zen Crescendos on our big island down under so its nice to have something a little 'exotic'!