I can help maybe just a bit. I went on a Great Speaker Hunt last year and listen to some floor-standing ProAc's. I was somewhat attracted to them, because they seemed darker sounding than everything else I was hearing (which included Spendors), and they remained on my list, but it was too hard to get any to my house, so I never had them at home. I became entralled with the British monitor sound, and now have the Harbeth Compact 7's, the Harbeth M30's, and the Spendor 1/2e's...which is ridiculous--I ought to be able to make up my mind...but I'm having fun. I think Compact 7's are excellent speakers. I'm going to guess that the ProAc's may sound a touch darker, but I think that there will likely be a family resemblance as between the ProAc's, the Spendors and the Harbeths.
I'll be interested to see any other comments to this thread.
I'll be interested to see any other comments to this thread.