Delta has taken over a lot of Terminal 4 at JFK. This is the International Arrivals terminal.They have added a lot of amenities and restaurants. The check in and bag drop areas are huge and the security lines moved fairly quickly, especially for the Friday before Christmas. The main hallway has many shops and restaurants, but don't worry if you are going to a gate with a high number - Shake Shack and Blue Smoke BBQ have outposts near gate B35, and there are very good coffee and pastry shops throughout the concourse.
Now flying Delta from NYC to San Juan has another interesting feature. You get to travel 2+ hours from to Atlanta and be only 50 miles closer to San Juan. And you get to see Atlanta Hartsfield Jackson Airport. When I was growing up a friend of mine used to say:
If you die south of the Mason-Dixon Line you have to transfer in Atlanta on your way to heaven or hell.And Harstfield Airport has often felt like being in hell, but I have found a part the airport that was normal, and one one of the heaviest travel days of the year. They have recently opened concourse F for international arrivals and departures, and that is where my flight was boarding (the plane had come in from Mexico City. There were very short lines at the restaurants and room to walk and breath. There were even more than enough seats available in the gate area even though my flight was over booked.
The flight was so over booked, mostly by cruise companies who like using Delta to get their customers to Puerto Rico, that Delta was offering $750 and over night accommodations for a flight the next day. I would have jumped at this, but The Amazing Ms. D would have killed if i didn't get down here today.