Personally, I'm not a fan of IO salts, however plenty of people use them and get good results.
Salt is almost a religion with many reef keepers. I'm not about to start a "salt war" over what the best salt it or how one salt compares with another. IMHO, it is impossible to prove that one salt is better than any other salt.
I will say that you should always use a quality salt, and that you get what you pay for.
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With all that being said it's interesting to see what the largest aquarium in the world uses... just Instant Ocean (not Reef Crystals).