I have three friends that own MCH-6 compressors under the MaxAir 35 brand name. All are very happy with them. Myself, I have a "vintage" 1980s Aerotecnica Coltri MCH-6 that I am also very happy with. Like SwimJim says, they are not intended for commercial use. Some of the things the Coltri factory recommends for getting the longest life out of an MCH-6:
1. Open the drain valves before starting. Then, let it warm up before closing the drains to start compressing air. You can rest your fingers on the 1st stage cylinder head and feel it getting warm and then let go when its hot. Then close the drains and pump air.
2. Don't overheat the compressor by continuous running. Turn it off and let it cool as needed between tank fills.
P.S. There ARE some MCH-6 threads on this forum