Expect to spend an hour in immigration, maybe longer. I had a brief visit (of about 12 hours on 3/4 July, flying in from Heathrow), but I was met by a mate with a car and taken on a quick tour of Brooklyn and Manhattan, having breakfast about 0300 in some Hungarian cafe, and taking a freebie trip on the Staten Island ferry, before being driven back to JFK with about three hours before my next departure to Narita. The AA lounge in Terminal 9 was quite pleasant. I had a shower - I certainly needed one, predawn New York was like a sauna - and sat by a window with my laptop, using the Wifi and drinking coffee to stay awake until my flight.Originally Posted by Homer
So my experience with JFK is pretty much limited to one AA lounge. Not unpleasant.