A. Aquaperform and Aquaversa are tested and certified by NSF International for NSF/ANSI standards #42 and #53 for health and aesthetics effects. Both are excellent Drinking Water Systems that provide the aesthetic and health benefits that you seek in a water filtration system. The main difference between these two systems is that Aquaperform provides the added feature of removing arsenic V from your drinking water supply, and has a stronger flow rate. If you do not have Arsenic V in your drinking water supply, as tested by a qualified and reputable municipal or private lab and you are not concerned about the presence of Arsenic V entering your drinking water supply in the future, you should consider getting Aquaversa to save on cost of the unit and replacement filters.