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 | PS Audio PMG S200 has more power - 100W against 80W into 8 ohms. That is about 1dB, which is a small step in loudness but real headroom on peaks. |
| Built-in DAC | B | Naim Uniti Nova has a DAC on board; the other needs an external one, which is another box, another power lead and another purchase. |
| Analogue inputs | B | Naim Uniti Nova takes more analogue sources - 2 against 1. |
| Use with a TV | depends | Only Naim Uniti Nova has HDMI ARC, so the television can drive it directly and one remote controls the volume. If the system is for music only, this changes nothing. |
| Headphones | depends | Only Naim Uniti Nova has a headphone output. Worth something if you listen late, nothing if you never do. |
| Amplifier class | depends | PS Audio PMG S200 is Class A/AB and Naim Uniti Nova is Class A/B. Class A/B runs warm and is the long-established mainstream choice. Modern examples of both measure well - judge by the rest of the page. |
| Shelf space | depends | Naim Uniti Nova takes up about 24% less shelf area (1371cm² against 1806cm²), and it is 90mm shallower, which is the measurement that decides whether a rack door shuts. |
| Price | B | Naim Uniti Nova costs less - $6,899 against $7,999 at list. |
A PS Audio PMG S200 B Naim Uniti Nova
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?
Naim Uniti Nova has the edge on paper, though not by much. The rows marked "depends" are more likely to decide this than the score is. If this sits under a television, Naim Uniti Nova is the one to buy - HDMI ARC means the TV remote controls the volume and there is no second box in the way. If you already own a DAC or a streamer, the built-in one is money you are paying twice for, and PS Audio PMG S200 becomes the more rational buy.
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.