Thoughts on Fixer

I usually use Photographers formulary TF-4, which is ammonium thiosulfate, I just checked the Freestyle website and their "Arista Premium Fixer" in liquid concentrate according to their MSDS is also composed of ammonium thiosulfate. Question: would these two fixers be basically equivalent or has the formulary added different ingredients to make theirs superior in some way. The formulary website does not give an MSDS for the TF-4 but the basic instructions for use of the two fixers is the same. Thoughts anyone?

Both are rapid fixers. There are several differences between these products. Chemicallly, TF-4 is alkaline pH, Arista Premium is acid. There is a substantual difference in dilution, TF-4 is 1+3, Arista Premium is 1+9. You also will want to consider the unit cost difference as well.