I started out with Tropic Marin and tbh, my tank was at it's best using this salt. I started adding more and more tanks (common issue for most of us) and it became too expensive to use.
I went to Instant Ocean after a little over a year using TM mostly because "EVERYONE" was using it and they "NEVER HAD A PROBLEM".
Neg: The salt is just way too dirty and parameters inconsistent from batch to batch. I also do not think the corals benefit from it as much as when I was on TM.
I switched to Red Sea after about 6 - 11 months with IO. The salt is much cleaner and pricing is good. Blue bucket with alk at 8 is great. It has been about 4 or 5 months now and I admit that acros are coloring back up again and everything seems to bounce back. Giving some time, I am sure the tank will be where I was when using TM.
I tried a batch of Fritz before Red Sea, but I can't remember why I didn't like it . The price is around the same for Red Sea but the source for each is different.
For now, I really do like the Red Sea and most likely sticking with it.