Second night of listening. Definitely a little clearer and better defined. Slight bump in midrange, which I like. Less bass (maybe 1.5dB), but I just bumped up my levels. Bass is crisper, too--kick drums and such--so it's wasn't just the treble tilt before I bumped the bass up. There's a little more air and three-dimensionality.
To wax poetic about the Quatros for a minute, man, they are fabulous speakers. The thing that I love about them is that they produce what you give them. Every tweak/change is to your system is heard. I've listened to a lot of high-end brands and have been impressed more recently by the revised Aerial 7T (or maybe it was 6T) and the new Revel Be line (I want to hear the Paradigm Be stuff now), but the Vandersteens just always sound so RIGHT. So real. I still haven't heard the CTs, but I am happy with these in a dual-use system for now. Maybe someday if I break it apart and have an even nicer dedicated two-channel system, I would get a second pair in CTs or Kentos/5A CTs, but it would have to be a deal. Quatros are definitely the price/performance sweet spot, IMO.
Since @holmz had brought up their surround performance, too, I will just reiterate how much I love them for surround, too. I have a VCC-Sig for a center (want a 5. I used to see them used all the time but now never do!) and standard VSMs for rears. I added a VSW recently for the .1 output in addition to the Quatros running full range for the fronts and was messing with it some last night, too. I had to reconfigure something in the Theta to make it work on the right port and finally did. I was demoing it all again with one of the few but favorite test discs for sound that I own--Sin City (and it kicks ass), and just wow. I don't even have the BR version, just the DTS. Everything is so precisely placed in space. Of course the Casablanca is doing an awesome job to help things, but the Vandersteens just again make everything seems so realistic.
Anyways... My .02