A. If there were one 'best' then it would be easy. The myriad possibilities in water source and qualities, as well as personal preferences (and pocket books) as to what constitutes 'good' water, makes choosing a filter a very personal choice. Choosing the right filter begins with understanding which contaminants need to be removed from the water. Suspended particles, dissolved inorganics, dissolved organics, microorganisms, etc. each present somewhat different challenges.