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 | 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 | evenly matched | Both behave much the same into 4 ohms - output increases strongly (160W and 150W). |
| Noise floor | B | Yamaha A-S3200 is the quieter design on paper - 114dB against 110dB. Audible mainly with sensitive speakers in a quiet room. |
| Built-in DAC | A | McIntosh MA5300 has a DAC on board; the other needs an external one, which is another box, another power lead and another purchase. |
| Analogue inputs | B | Yamaha A-S3200 takes more analogue sources - 7 against 5. |
| Room to grow | A | Only McIntosh MA5300 offers a pre-out/main-in loop - which decides whether you can add a subwoofer or a power amplifier later without replacing the box. |
| Shelf space | depends | Yamaha A-S3200 takes up about 14% less shelf area (2136cm² against 2488cm²), and it is 68mm shallower, which is the measurement that decides whether a rack door shuts. |
| Price | A | McIntosh MA5300 costs less - $6,000 against $8,000 at list. |
| Watts per dollar | A | McIntosh MA5300 is the cheaper watt - about $60 per watt against $80. A blunt measure, and it says nothing about how either sounds, but it is the honest one for raw output. |
A McIntosh MA5300 B Yamaha A-S3200
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 MA5300 has the edge on paper, though not by much. The rows marked "depends" are more likely to decide this than the score is. If you already own a DAC or a streamer, the built-in one is money you are paying twice for, and Yamaha A-S3200 becomes the more rational buy. Think about the whole system: the roughly $2,000 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.