The Winix units are designed for dust and pollen hence the heppa. The automatic air sensor only senses molecule changes in the air quality (smells) and not pollen and dust on the auto mode. I keep mine at level 2 all the time and hardly notice it. First level is basically silent, but not sure it moves enough air.
It takes up less room being square and looks more modern. On the bad side it’s a freakin light show with all it’s settings. I had to put some tape over them to sleep with unit on second speed. On auto it has a sleep mode which tones things down. I can’t help but think that if you kept this on automatic you would be disappointed in your air results.
As for the plasma thing, I’m not sure mine works at all no sound difference or air change. Will this make the air better than the honeywells; no but it works well according to what speed you set it on and can approach their effectiveness on turbo but who wants to listen to that. Unit also does well to suck animal hair out of the air. Have a cat that walks into the room and you would think he exploded, takes care of all that.