One is a streaming all-in-one and the other is an amplifier. Judge them on how many boxes you want and what you already own, not on the spec sheet alone.
| Area | Better | Why |
|---|
| Power | evenly matched | Effectively the same output - 100W against 100W into 8 ohms is under 1dB, which is not an audible difference in loudness. |
| Grip on hard loads | A | Marantz Model 30 holds up better into a 4-ohm load: its output nearly doubles to 200W, where the other increases modestly. That matters with demanding speakers far more than the 8-ohm figure does. |
| Built-in DAC | B | Marantz MODEL M1 has a DAC on board; the other needs an external one, which is another box, another power lead and another purchase. |
| Streaming | B | Only Marantz MODEL M1 has AirPlay 2, Roon and HEOS. |
| Analogue inputs | A | Marantz Model 30 takes more analogue sources - 6 against 3. |
| Phono stage | depends | Marantz Model 30 has a built-in phono stage (MM,MC) and Marantz MODEL M1 does not. Decisive if you own a turntable, completely irrelevant if you do not - and an outboard phono stage is easy to add later either way. |
| Room to grow | evenly matched | The same expansion options on both. |
| Shelf space | depends | Marantz MODEL M1 takes up about 73% less shelf area (552cm² against 2033cm²), and it is 206mm shallower, which is the measurement that decides whether a rack door shuts. |
| Price | B | Marantz MODEL M1 costs less - $1,000 against $2,999 at list. |
| Watts per dollar | B | Marantz MODEL M1 is the cheaper watt - about $10 per watt against $30. A blunt measure, and it says nothing about how either sounds, but it is the honest one for raw output. |
A Marantz Model 30 B Marantz MODEL M1
depends neither is better in the abstract - it turns on your room, your system or how you will use them. Only specs published for both amplifiers are judged; anything missing on either side is left out rather than guessed.
Which should you choose?
Marantz MODEL M1 has the edge on paper, though not by much. The rows marked "depends" are more likely to decide this than the score is. If your speakers are a difficult load - 4 ohms nominal, big woofers, or a sensitivity in the low 80s - Marantz Model 30 is the safer partner, because how an amplifier behaves when the impedance drops matters more than its 8-ohm rating. If you play records, Marantz Model 30 saves you buying a phono stage; if you do not, ignore that row entirely.
What a spec sheet cannot show: how either sounds with your speakers, how the controls feel day to day, and what the app is like to live with - which is where most all-in-one amplifiers are actually won or lost. Power figures are the manufacturers' own and are not measured to a common standard, so treat small differences as noise. If you can hear both, that will tell you more than any row above.