Harbeth 40.2 or Vandersteen Quatro CT

Of all the speakers I've heard, including Vandersteens, high-end KEF, and Wilsons (sorry, don't recall which models), the 40.2s were the ones I loved the most.  I'd keep 'em.

+1 on contacting John Rutan (audioconnection).
He will give the dope on what you need to know.
Great advice, and free from pressure.
Bob

They are very different speakers.  If you value things like 3D imaging/soundstage, extended bass, and neutrality there’s a lot you’ll like about the Quatros.  But if it’s more the “sweetness” and smooth sound of the Harbeths you might feel a little left out in the cold with the Vandys.  To my ears, speakers that kind of bridge the gap a little more would be Verity Audio or Sonus Faber, or maybe even ProAc.  Best of luck in your search. 

I agree with Soix. Having owned the Vandersteen Treo CT and the Harbeth C7 and M30.1. You can’t go wrong with either, but I warn you. You may have regrets selling your Harbeth. Vandersteens do have an awesome soundstage and imaging to die for...completely disappears in the room, but there is something magical in the mid range of the Harbeths that keeps pulling me back. The Vandersteen are truly awesome for reproducing live music...best I’ve heard, but if you play a lot vocals and jazz, I think the Harbeths have an edge. Just my opinion. I would not make any decision until you’ve had a chance to audition the Vandersteens somehow.

And if you do go with the Vandersteens, the Pass Labs amps will probably hold you back from what they are truly capable of. I say that as a former owner of XA 60.8s, but I have not heard the 260.8s. A no global feedback amp is a better choice. I have the M5-HPAs which were a major improvement. Gone was upper midrange glare. Welcomed was a better sense of realism and immediacy.