Product review (3 stars): Gambled, and lost...get what you pay for...
I have not used this (RFC0900A, aka Maytag Ukf8001 compatible...) yet...I took a gamble that this would be certified to remove as many contaminants as the Maytag pur water filter.  Gambled, and lost... I suppose it might, but it is certainly NOT certified to do so.
In fact it is only (per their Performance Data Sheet) certified to remove Chlorine Taste and Odor (see picture) at an average percent reduction of 99.06%. Conversely, the The Maytag pur UKF8001 is certified to remove, Lead, Mercury, Chlorine Taste and Odor 97.52% average, Particulates, Asbestos, Cysts & Turbidity and more....

It is interesting that RFC0900A is slightly better at removing Chlorine Taste and Odor (1.54%), but as far as other contaminants go, who knows; unless they get certified for the other contaminants.  One could conjecture that they would get certified, if they could, but until they do, or if they ever do, we won't know...  I will just buckle down and pay more for the certified product, the Maytag UKF8001.

I gave this 3 stars, because it does what it was advertised to do....just not what I had hoped...