I use it and have nothing but good things to say. It helps to keep the tank clean and algae at bay. I have been running it since my cycle finished about 10 months ago. I only have to clean my glass every 7-10 days on my 270g. My wifes tank(165) does not use this product and she is cleaning the glass every 2-3 days. I almost always have no visible algae and my corals seem to thrive so far in my tank. I have 90% SPS, about 50 frags. I dose every other week as directions say and the only way I could be happier is if it was cheaper. Runnig any additives on large tanks can get pricey though and I expected the cost upon making the decision to go with Prodibio. I believe many people who use it also run biopellets as I do. That statement may not be true though.
I went with Prodibio after seeing several tanks that run it and I was impressed with the results they had. Lot of options, but it has worked to my satisfaction.