NIST has specific relevance to businesses providing services to the US Federal government and the US Federal Government itself. From a business standpoint, ISO (International Standards Organization) compliance probably has more cachet because it is one of a suite of business standards that a company can mention on its website. ISO may be a better fit for an organization doing business outside the US simply because it's 'International' and more available to local security managers.
In the end, the choice of one or the other is perhaps more of a business decision than a technical decision. A good implementation of one or the other will be helpful. A bad implementation won't.