Mark, you are asking the wrong person if you were asking me...all I can tell you is that I have a less than 2 week old H/K 635 with a less than day old Rotel 1080 amp/1070 preamp and I can audiably tell a difference with the very same speaker used for both.
I believe the A/V HK 635 will do it's job just fine with the 60s HT system in the den and I equally believe the Rotel/80s will fit my bill to an absolute 'T' in the main and larger living area. If not, I'll ship the 80s back before the 30 day limit and look elsewhere, I've never been bashful in that department.
Scientific data? Couldn't tell you a thing about it, but I will say my wife and I both feel that the Rotels sound better than the HK running the 60s. As long as I feel like a great choice was in both directions, that's all that matters to me...and my wife!
