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 | B | OSD Nero Stream XD has more power - 30W against 22W into 8 ohms. That is about 1.3dB, which is a small step in loudness but real headroom on peaks. |
| Noise floor | evenly matched | Much the same signal-to-noise ratio (95dB vs 95dB). |
| Built-in DAC | B | OSD Nero Stream XD has a DAC on board; the other needs an external one, which is another box, another power lead and another purchase. |
| Analogue inputs | A | Audioengine N22 takes more analogue sources - 2 against 1. |
| Room to grow | evenly matched | The same expansion options on both. |
| Amplifier class | depends | Audioengine N22 is Class A/B and OSD Nero Stream XD is Class D. Class A/B runs warm and is the long-established mainstream choice; Class D runs cool and draws almost nothing at idle. Modern examples of both measure well - judge by the rest of the page. |
| Shelf space | depends | Audioengine N22 takes up about 47% less shelf area (202cm² against 384cm²). |
| Price | A | Audioengine N22 costs less - $199 against $240 at list. |
A Audioengine N22 B OSD Nero Stream XD
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: OSD Nero Stream XD measures better, Audioengine N22 costs about 17% less. With most speakers in most rooms that gap is smaller in practice than it looks here. If you already own a DAC or a streamer, the built-in one is money you are paying twice for, and Audioengine N22 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.