Nearly all contaminants are removed at levels above 90% - most of them around 99%. Chlorination byproducts (the risk with chlorine) were removed at 99.6% or better in independent tests. Even chloramines are removed up to a 95% rate. Fluoride is reduced by about 75% to 80%.
Might be good for those who don't want to get a distiller and don't have a reverse osmosis system.