Product review (1 stars): only improves taste; does not make water safer/cleaner
I was checking out these filters to replace the more expensive GE filters.  According to Water Sentinel themselves, these filters are certified against ANSI/NSF Standard 42, and only Standard 42.  That standard is soley for aesthetics; that is, the filter removes chlorine that makes the water taste bad.  The GE filters are certified against ANSI/NSF Standards 42 and 53.  Standard 53 is for the reduction of lead, mercury, Giardia and other cysts, asbestos, and many other chemicals.  The Water Sentinel filters do not claim  that they are certified to remove these items.  So, although the water tastes better than tap water, it may not be any safer than tap water.  If you're buying filters only to improve the taste of the water, these are definitely less expensive than the GE filters.  If you're buying filters to improve the safety and quality of the water, you may wish to look at other filters.

From the ANSI website:

NSF/ANSI Standard 42: Drinking Water Treatment Units - Aesthetic Effects
Overview: This standard covers point-of-use (POU) and point-of-entry (POE) systems designed to reduce specific aesthetic or non-health-related contaminants (chlorine, taste and odor, and particulates) that may be present in public or private drinking water.

NSF/ANSI Standard 53: Drinking Water Treatment Units - Health Effects
Overview: Standard 53 addresses point-of-use (POU) and point-of-entry (POE) systems designed to reduce specific health-related contaminants, such as Cryptosporidium, Giardia, lead, volatile organic chemicals (VOCs), MTBE (methyl tertiary-butyl ether), that may be present in public or private drinking water.