Maritime patrol aircraft benefit from a mass-produced airframe

Would the US Navy choose a Boeing 757 or an MD-90-based maritime patrol aircraft?

Probably the Boeing, because a mass-produced airframe provides a much stronger supply and support network.

The lesson drawn from Nimrod is logistical as much as aerodynamic. A commercial type already produced in large numbers brings abundant spares and experienced maintainers. It also offers a deeper support base for a patrol aircraft expected to remain in service for decades. That makes the Boeing 757 more attractive than a bespoke MD-90 variant, and a later exchange accepts retired British Airways 757s as potentially sensible conversion candidates.