I would think a buyer would want some type of standard say ISO 2858 or ANSI B73.1. Then there is the next step into API610.
I think its all about the industry you are in. For me I perfer the ANSI B73.1 as they historically had a better range of metallurgy for the inorganic chemicals I work with (acids, salts, water, etc). I don't think either metallic mag drive or "plastic" lined mag drive or non mag drive have replaced either the ISO or ANSI market.
To me (and that IMHO) the ISO series is more a European type standard. In my industry we don't see much of them at all.
Good luck