No single best speaker here - they are built to different priorities, and the right one depends on your room, your sources and what you listen to.
| Area | Better | Why |
|---|
| Bass | A | Kanto YU4 digs deeper - 60Hz against 76Hz. |
| Built-in power | A | Kanto YU4 has the bigger amplifier (70W vs 50W RMS). |
| Connections | A | Kanto YU4 adds phono. |
| Size | depends | Kanto YU4 is easier to place; Jamo S 801 PM is bigger, which usually goes with fuller bass. Your room decides. |
| Expandability | depends | Kanto YU4: a sub output; Jamo S 801 PM: a sub output. Jamo S 801 PM sits in a wider range (7 models), so a matched surround system is easier later. |
| Price | B | Jamo S 801 PM is cheaper - $300 against $450, about 33% less. |
A Kanto YU4 B Jamo S 801 PM
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 speakers are judged; anything missing on either side is left out rather than guessed.
Which should you choose?
The usual trade-off: Kanto YU4 measures better, Jamo S 801 PM costs about about 50% more% less. Whether that gap is worth the money is the call only you can make - and in a normal room it is often smaller than the numbers suggest. If a subwoofer is in your plans, the bass gap largely stops mattering - you would be crossing over above 76Hz anyway, which makes the cheaper Jamo S 801 PM much easier to justify. In a large or open-plan room, Jamo S 801 PM has the cabinet volume to fill it more easily; in a small room, near a wall or at desk distance, Kanto YU4 is the easier speaker to get right.
And remember what a spec sheet cannot show: how each looks in your room and whether the finish suits it, what dealer support and warranty are like where you live, and how they actually sound to you. If you can hear them first - ideally with your own music - that will tell you more than any number above.