Lots of opinions, the bottom line is most are good. The control is test your water and have a good test kit set. Get a refractometer and start with the proper salt mix (salinity). Don't buy a plastic float clear "doesn't get it right" gauge, they are notorious for being WRONG. Mix your salt before you add it to an existing tank and don't expect your meter to give you an accurate reading until your salt has been in the water for several hours and has been agitated by some kind of pump system. You can however mix your salt and water in an empty NEW tank.
But I think you already knew this, I see now you have 111 posts. ..wink...
I have used about every brand you can find and have never had a problem. I now buy by price. But, I dose calc, alk, Kent iodine, and trace elements, so I may would never know the difference.