What were the best years for McIntosh power amps...

... I want to buy a Mac but I must buy used. I need power so new is way outta bounds. I had a MC 7100 but she wasn’t man enough for the speakers I have. 
So what speakers do you have? Have you thought about the MC7200, which has twice the power of the 7100? This amp is also direct-coupled, so you don't have the autoformers to get in the way. The 7200 might be a bit hard to find, as most guys hang onto them. I've had mine since they originally came out, and would never consider getting rid of it. My speakers are old, ADS 1590/2's, and this amp handles then quite nicely. My ears start to bleed long before this amp runs out of steam!
As to your question, the answers will be subjective at best, along with the autoformer design. I understand the newer amps are quite good, but the prices are hideous to go along with it. 
I have the Aerial 10T’s so same family of speakers. I LOVE the 1590’s! I’ll look around for the amp. Thanks!
What were the best years for McIntosh power amps
The original 275 were their best years.
Then ss with output transformers??????????????????

Cheers George