I dislike instant ocean, and have not used the others. But around here the general consensus is tropic marin pro is top dog but pricey.
I have used a few different and tried oceanic and have not used anything else since. Disolves fast and clear. and lots of calcium. No one sells Tropic marin around here so i have not had a chance to use it, i would try it if i could find some.
Reef crystals is made by IO so im not messing with it.