Hey Adiorio,
With the amps you are considering, I would choose Plinius. Why? I've owned Krell and what Brm1 said, i find to be quite accurate. The Krell just displayed no musicality what so ever. I've also auditioned a McCormack amp when i tested, what will become my main speakers, the Revel Performa F-30's. They were fabulous together. There was so much detail and such a grand soundstage, I fell in love. I've recently upgraded my Krell amp to the plinius SA-250 on the recommendation of a friend in the audio biz. I have never heard anything like this in my home. In fact, I don't remember hearing anything close to this since i went to the Hi-Fi show at the Waldorf back in '96. I have this amp driving the Revel Performa M-20's that will become the rear ch's when the F-30's are added. Anyway, these speakers just sing with the plinius amp. I find myself close to tears listening to how beautiful my music sounds. Discs that i have listened to a thousand times, now sound so much better, i can't believe it. I have nothing against the MacCormack amps. If you choose to purchase one, you will not have any worries, they are excellent amps. But, IMHO, the plinius should be given serious consideration. Happy hunting.....John