They are all about the same. What you want is flow rate. Meaning 99.9% efficiency high end filter is not that much more than 99%. But if air gets filtered 2x vs

They are all about the same. What you want is flow rate. Meaning 99.9% efficiency high end filter is not that much more than 99%. But if air gets filtered 2x vs 5x every hour then the 5x worse filter will probably be better So just make sure to not place the air purifier in a corner, but more central. And turn it up to a higher power. Or run your AC fan continuously