No single best amplifier here. What decides it is what you have to drive, what you need to plug in, and how much of the system you want in one box.
| Area | Better | Why |
|---|
| Power | A | McIntosh MC152 has more power - 150W against 100W into 8 ohms. That is about 1.8dB, which is a small step in loudness but real headroom on peaks. |
| Analogue inputs | A | McIntosh MC152 takes more analogue sources - 2 against 1. |
| Price | A | McIntosh MC152 costs less - $6,500 against $8,999 at list. |
| Watts per dollar | A | McIntosh MC152 is the cheaper watt - about $43 per watt against $90. A blunt measure, and it says nothing about how either sounds, but it is the honest one for raw output. |
A McIntosh MC152 B Naim NAP 250
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?
McIntosh MC152 is the easier recommendation: it leads on most of the measured areas and costs less. Take Naim NAP 250 if one of the "depends" rows above describes your system. Think about the whole system: the roughly $2,499 saved by taking the cheaper one would buy better speakers or a subwoofer, which does more for the sound than the difference between two competent amplifiers.
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.