I just picked up a pair of vintage MC-30's from Audio Classics and find them to be one of the best / most enjoyable amps I've ever owned in 30+ years in this hobby. Amazing to me that gear from the 1950's can sound so damn good!
Other Mac gear I've owned has been a mixed bag...
- MC275 MKV was very good and enjoyable. Recommended.
- MC220 preamp was just "ok"... felt music was a bit veiled, but I probably could have coaxed more out of it with tube rolling.
- MC2275 tube integrated was disappointing. Very soft and veiled sounding.