I might be on an island on this but I am a big detractor from salt in general as it applies to hot tubs.
To clarify - I am very aware from first hand experience that salt systems in pools are terrific (the technology has progressed and the product is both widespread and way beyond the first generation and thus the bugs are worked out and cost is way more palatable), that "salt" isn't always NaCl (there are bromine systems that are dubbed as salt, fyi), there are different brands / applications of salt systems in the industry, and it is not always an apples to apples in terms of discussing the specifics as it relates to hot tubs.
Seeing the back-end from a manufacturer's point of view, (and to further the point made by cranbiz in the above post) there is a lower life span in the cells that I see. The upkeep and cost of both the mechanical aspects and the chemical aspects really hinder all the positive aspects. This is further compounded by easier products to manage (such as, but not limited to, @ease) that give you many (if not all) of the benefits of the salt system w/o the cost and maintenance.
And maybe this next point isn't fair as it is based on pure hypotheticals (so I understand the flaw in my own point I am trying to make), but if this industry wasn't heavily-based on commission, and had more back-end information from service techs available to share knowledge, I wonder how the narrative would be framed in terms of this discussion.
BUT - I must also admit that there is nothing but positivity in the feedback from my customers who did indeed go the salt route. Furthermore, I understand my whole issue with the product is based on both cost and maintenance and for some that is a total non-issue. Thus all of the above notes may not at all be salient to you.
Clear as mud, right?
Hope this helps. Good luck moving forward.