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 |
|---|
| Built-in DAC | evenly matched | Both have a DAC on board with much the same capability. |
| Streaming | A | Only Marantz M-CR612 has AirPlay 2 and HEOS. |
| Room to grow | evenly matched | The same expansion options on both. |
| Built-in sources | depends | Marantz M-CR612 has a CD player built in. That is one less box if you still play discs or listen to radio, and dead weight if you do not. |
| Shelf space | depends | Yamaha WXA-50 takes up about 33% less shelf area (572cm² against 849cm²), and it is 36mm shallower, which is the measurement that decides whether a rack door shuts. |
| Price | B | Yamaha WXA-50 costs less - $599 against $650 at list. |
A Marantz M-CR612 B Yamaha WXA-50
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?
The usual trade-off: Marantz M-CR612 measures better, Yamaha WXA-50 costs about 8% less. With most speakers in most rooms that gap is smaller in practice than it looks here.
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.