While I do believe it is about what you like...........there are differences in salt brands. The different parameters giving by each brand will aid you in what you want to achieve with your tank.
For instance, some salt gives high Calcium. While other willl give you low Calcium. Choose the salt that helps YOU run the tank the way YOU want it.
Your tank is also going to tell you what it wants. Depending on how you stock it, your demands, will be different from others tanks. You may need a high Calcium salt, while another may not. I am not mentioning Alk cause in the end Alk doesn't really mean a darn thing. A 20% water change with a high Alk salt isn't going to effect you water. The reserve power just isn't there.