I’m impressed with the cleanliness of my vacuum pot’s coffee. It leaves a lot less sediment as compared to french press, and that last swallow is tolerable rather than being nasty. The reason a vacuum pot leaves less dust in the cup is that the coffee is pulled through a filter bed forrmed by the grounds.
This photo was taken immediately after the kickdown, the dusty scum is clearly visible on the sides of the bowl.
Here I pulled out the rod from the filter bed, you can see how the dust stayed on the top layer.
Another shot showing the clean and dirty layers.
Compare this to a press pot where the grounds & dust remain suspended in a slurry underneath the plunger. When pouring a cup the grounds aren’t compacted enough to form a filter bed and the metal screen certainly isn’t going to stop them.
There’s a strong analogy between this and a lauter tun (this is a beer site afterall). The brewer takes care to form a good filter bed for the lautering process and the grain does most of the work keeping the wort clean.