I think over the years I have used just about every salt mix and have never been totally satisfied with any. Most work fine for hardy corals and all types of fish and inverts. The results of studies such as the one linked in this thread now give some quantification. For my fish and invert systems and my soft/LPS coral systems I use Instant Ocean and it seems to do a good job for me. For my SPS coral systems I now use natural saltwater. I am very happy with the reults of this water after using it for a year now. I set up some 12 gallon nanos about 8 months ago and used this water from day one and change 4 gallons a week while adding no supplements at all and so far after 8 months the corals in these 3 nano tanks have done super with great growth and coloration. One is set up with soft corals and zoos, one with LPS corals, and one with Acros and Montis.
For a number of years I used and sold Crystal Sea salt mix. I never had any problems with it, but many customers did see bleaching and other issues so I switched to Oceanic. It was not the answer for me and then I switched to Instant Ocean, the salt I started with back in 1968 when I started in the hobby. It was fine for most of my systems, but I had some issues in my SPS greenhouse system. Last year at MACNA the Nature's Ocean Nutri Seawater (NSW) was supplied and I liked the results there and have used it since for my SPS. In my experience and opinion you can not do better than natural seawater. The bottled seawater is likely too expensive for most average hobbyists and in some areas other natural seawater options may be available, I think it is worth looking into using NSW considering the almost weekly threads about bad batches of salt mixes and results of recent studies. I test every batch of salt regardless of NSW or IO, and test my SPS system daily for all parameters and weekly on all other systems. Most important thing is get and use good tests and then you don't have any surprises as far as the major parameters.