Interesting thread.I have a 12 year old pair of 3A Sigs. I have done a lot to squeeze out the best possible performance out of them over the years within my means. Recently I thought about selling them and getting the new Maggie 1.7i. I love Maggies and have a pair of 1.6's in another system. I consider that my reference system in many ways. Lately I've been re-thinking my thoughts on selling the Vandy's though. They seem to surprise me every time I change something in just the slightest way, like toe in, repositioning them, tilt back, cable changes, adding a line conditioner, changing seat height, other tweaks for ground control, lowering the noise floor, etc.Today before I stumbled upon this thread I was comparing the two systems with the same tracks, in different rooms of course and they both had a lot to offer. The Maggie's with a Vandy sub just don't have the same kind of bass fullness of the 3A Sigs.However it's all there and articulate! The Vandy's bass is pretty spectacular and also very accurate and detailed when fed the right upstream components and the synergy is there. The Maggies are a special breed and are breathtaking in what they have to offer as well. Two different flavors and both delicious. Barolo and Rioja: take your pick. It felt great to hear them both deliver the goods in all areas. The Maggies just move air in a different manner and when I listen to them I do not "pine" for the bass of the Vandy's. It's there but rolls out in a different way. The Vandy's are remarkable in the way they do bass and detail together. It's all there really with both speakers. Just different delivery.
As far as the 3's vs The Treo's I think they are quite different in the same way and each have their strong suits. I've heard the Treo's many times at John Rutan's Audio Connection and they are SOTA speakers for sure. I would say they are more "fleet" in their delivery, but the newest versions of the 3A Sigs are incredible in their own way to my ears. I have an older version and like I said, they surprise me every time I think I may want to change them. Vandersteen has a wonderful line of loudspeakers to fit all budgets. They can really deliver the goods especially when there is synergy with your components and you set them up properly. I've heard the entire line many times and they are a terrific value. Same can be said about the Magnepans IMHO of course. If you can hear the 3A Sigs and Treos side by side with the same components, that would really be the determining factor as to what you prefer.