Product review (4 stars): Good for taste. Not too hard on the wallet.
Works fine when installed correctly.  Mine now whistles occasionally. This is likely due to a small air pocket in the filter that I didn't fill during initial install.  This filter is mainly for taste and heavy metals. Don't expect miracles if you have really terrible water.

Having said that, it has the listed certification, so it does what it needs to.  TDS and heavy metals aren't a problem in my area, so I can't say much to it's ability to handle poor water conditions.

I hope this review helped you in your research.