I bought and installed this about 1.5-2yrs ago.  Like other reviewers the cold (others had hot as well) water handle is no longer turning.  If you apply pressure instead of turning as it did the entire cold water fixture rotates and loosens.  This is obviously not by design.  Today I've removed the handle to see if there is something within it that will free it up but I'm not seeing anything that can be done short of purchasing a new handle, if that is even available.  Like others with this same problem, I believe
this product should last more than 1.5 years without requiring replacement.