Different price classes - Yamaha R-S202 costs roughly 2.8x what Fosi Audio V3 does. Expect it to lead on paper; the question is whether you will hear the difference through the speakers you own.
| Area | Better | Why |
|---|
| Phono stage | depends | Yamaha R-S202 has a built-in phono stage and Fosi Audio V3 does not. Decisive if you own a turntable, completely irrelevant if you do not - and an outboard phono stage is easy to add later either way. |
| Amplifier class | depends | Fosi Audio V3 is Class D and Yamaha R-S202 is Class A/B. Class D runs cool and draws almost nothing at idle; 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 | Fosi Audio V3 takes up about 89% less shelf area (172cm² against 1506cm²), and it is 242mm shallower, which is the measurement that decides whether a rack door shuts. |
| Price | A | Fosi Audio V3 costs less - $90 against $250 at list. |
A Fosi Audio V3 B Yamaha R-S202
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?
Neither runs away with it - they trade advantages. Let the "depends" rows and the speakers you already own settle it. If you play records, Yamaha R-S202 saves you buying a phono stage; if you do not, ignore that row entirely. Think about the whole system: the roughly $160 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.