Product review (4 stars): Keeps the water fresh tasting
These are a little pricey but they do last for six months at a time so that helps.  A little awkward to install if you are short, like I am, but a stool takes care of that problem.  This is my third replacement and I did have some strange noises and a little bit of water on the initial flushing.  I removed it and reinstalled, still had the noises but no water overflow so it was probably some user error.