I own the Classe CA300, paired with Vienna Acoustic speakers. I've been told that Classe is a good match for Martin Logan, due to the smooth sound of Classe amps. I love my CA300.
Having said that, I have not auditioned the BAT or McCormack under controlled conditions, so can't help you directly with your comparison. I do believe BAT has a reputation for being less "warm" or "euphoric" than other brands of traditional tube gear (such as Conrad-Johnson). BAT has a great reputation, however. Had I not purchased Classe, BAT would perhaps have been my next choice.
Having said that, I have not auditioned the BAT or McCormack under controlled conditions, so can't help you directly with your comparison. I do believe BAT has a reputation for being less "warm" or "euphoric" than other brands of traditional tube gear (such as Conrad-Johnson). BAT has a great reputation, however. Had I not purchased Classe, BAT would perhaps have been my next choice.