@audiofile10, I never purchased the MC275, although I might at some point, need to demo it first. I sold both the C2300 and MC-152, not a big fan of Mac preamps. I have also owned the C220 before.
I think the MC-152 is a good amplifier, maybe under-rated compared to its bigger bros.
I have not heard the ZOTL 40, can't help you there, check your speakers sensitivity and look a bit in youtube and elsewhere if someone is using ZOTL40/and your speaker and what impressions they have.