I dunno about all that "does well with room modes" comment above, but I do know that the Vandies remind me an AWFUL LOT like the old Mirage M series stuff! Warm, a bit lacking in ultimate detail and resolve, as well as that "blanket over tweeter" sound to me. Basically, they sound laid back, reserved, a bit colored, warm, and not so extended and lively. To me, these are the antithesis of a Thiel speaker.
Yeah, if I had to own a pair of Vandersteen's, or Mirages for that matter, I would probably hook em up to hear music and such. Soon thereafter however, I'd have to change em out for a more accurate transducer that didn't add so much to the signal, and basically server me an overly wamred and veiled sound.
I don't mind a little warmth from a speaker if need be, like what Paradigm and Sonus Faber, PSB, B&W, Kef and Tannoy, have traditionally tended to offer. But I simply feel the Vandersteens do what Bob Harley's book "Complete Guide To High End Audio" recommends against for a speaker, and that's "errors on the side of addition" rather than "subtraction"! In the case of the Vandersteens, they're simply adding their own character to the sound to my ears.
To each his own howerver. For me, I'd have to at least chose Thiels.