Hasse,
The Mac (from that generation) was sweet and easy to listen to, nice midrange. The KSA 250 was one of the most powerful sounding amps I've ever had and I thought better than the Mac overall. The 100.5's are my favorites. Low level detail is beyond the others, sweet class A midrange and a non fatiging high end. Interesting thing on the MC1000's, even with all that power, they lost what I liked about them as I turned the volume up even though I was well below the 1000 watt mark. But most of my listening was at the .5 to 50 marks on the meter so it wasn't an issue. The Krell and Pass kept/keep their sound as the volume went up.