CM's Max 9s have lie flats in J, but I don't think those are flying JFK-PTY. About 40% of their 738s (the 738B) have barcaloungers in J (which are considerably better than the UA domestic F recliner). Not sure whether JFK is a dedicated 738B route.
Economy on CM is pretty miserable for a long flight.
Originally Posted by
IAH-OIL-TRASH
Business w/ either gets you United Club access at EWR.
It's debatable whether that's better than a sharp stick in the eye.