Product review (5 stars): Whiskey lover's dream
I bought these to make better cubes for some ultra premium Rum and bourbons that I have been buying lately.  So far, I have only tried with filtered water rather than tap.  But the quality of the cubes have been very good.  They are super clear and slow melting.  Drinks are chilled, but not too watered down.  I am still contemplating the difference between the experience of these cubes and whiskey stones.  Both are good.  It really depends on what you are trying to do with your drinks.

The cubes release well on the first use.  It will be interesting to see how well the do as time goes by.  The silicone should allow it to release well with multiple uses between washing.  But I might be just obsessed enough not even try that out.