I believe there are two broad considerations when selecting a salt:
1. Quality of the salt (production) - often indicated by 'instant' mixing capability
2. Target parameters of the salt
For quality, I would only select salt produced by Tropic Marin, which includes the one John stated, or Fauna Marin (less widely known but also made by Tropic Marin). They had a big scandal some time ago regarding quality after being in the business for decades but have learned their lesson.
For target parameters, I would determine what you believe is what you want in your tank. Looks like some of the AF salt variants have higher dKH, higher MAG, and higher CA than typically considered desirable range, while others have far lower values. This can be useful in certain circumstances but depends, and I personally would not select that. I was not able to find the standard AF salt parameters, so if you do, please post here.
Of course, AF is distributed by BRS, so you can expect many positive reviews on R2R, etc.

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Another aspect is price and availability. Both Tropic Marin and FM salts are probably the most expensive salts, and not all tanks need that. AF reef salt (standard salt variant) seems similarly priced as FM and, if TM salt is on sale, AF seems to be available on chewy.com too, which makes this a + in terms of availability.
In summary, unless AF salt offers a unique trace spectrum which you would like to aim for, I do not see any benefits going with this salt unless you get a good deal or the Tropic Marin or Fauna Marin salts are not available.