I am very impressed with the Krell KSA-100. I have two stereo amplifiers that I use as monoblocks, so my impression might differ slightly than if someone simply had one stereo amplifier.
The Krell has great air and space around the instruments, and does offer a very nice sound stage. It has a rich, warm sound, with a musical presentation. Vocals are very clear, as well as bells, brass, and percussion.
You identified the major weakness of the Krell: its timbre. There is only slight distortion to the string instruments, which cause them to sound only slightly synthetic. Occasional wind instruments, like the oboe, would sound tinny (although most wind/brass was excellently portrayed). One last weakness of the Krell is its lack of delicacy: it has less decay/fade on the sounds.
By comparison, using the same RCA cables, the Lamm M2.2 is clearer and warmer with more dynamism, and separation of the instruments. It offers a more lively presentation with cleaner and clearer brass/wind instruments, with no tinny sounds.
The Lamm M2.2 with the XLR is another notch or two above the Lamm with the RCA.
Overall, I would be very content with the Krell KSA-100, and you wouldn’t miss anything musically, nor would you see how things could sound much better than with the Krell. . . but then you listen to the Lamm, and they do!