I use it and have had great results w/ it. It really seems to promote coralline and made my button polyps look awesome.
It didn't seem to live up to the claim that it keeps ich from attaching to the fish, but what product does? As for the hair algae I had a massive breakout and it went away while I was using it , but I'm not sure if it was because of the reef vital or the yellow tang that gorged on it and my constant pulling it from the rocks. Cleaning my skimmer thoroughly and often helped immensely too.