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 - 90W against 100W into 8 ohms is under 1dB, which is not an audible difference in loudness. |
| Room to grow | B | Only Yamaha R200A offers preamp outputs - which decides whether you can add a subwoofer or a power amplifier later without replacing the box. |
| Price | A | Sony STR-DH190 costs less - $248 against $300 at list. |
A Sony STR-DH190 B Yamaha R200A
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: Yamaha R200A measures better, Sony STR-DH190 costs about 17% less. With most speakers in most rooms that gap is smaller in practice than it looks here.
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.