Both are NAD, from different ranges - the engineering approach is shared and the differences are mostly in power, connectivity and price.
| Area | Better | Why |
|---|
| Power | evenly matched | Effectively the same output - 150W against 185W into 8 ohms is under 1dB, which is not an audible difference in loudness. |
| Speaker load rating | A | NAD M32 is rated down to 2 ohms against 4, so it is the safer partner for a low-impedance speaker. |
| Bass control | evenly matched | Similar damping factor (800 vs 800). |
| Analogue inputs | A | NAD M32 takes more analogue sources - 4 against 2. |
| Price | B | NAD C298 costs less - $3,099 against $3,299 at list. |
| Watts per dollar | B | NAD C298 is the cheaper watt - about $17 per watt against $22. A blunt measure, and it says nothing about how either sounds, but it is the honest one for raw output. |
A NAD M32 B NAD C298
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: NAD M32 measures better, NAD C298 costs about 6% 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.