I find the AA transcon F product best in class.

From LAX, can access the QF F lounge and arrive at JFK Flagship lounge for a private shower/washroom (can't deal with public facilities) before heading into Manhattan. While B6's Mint (especially the 4 private ones) is a fine product, the lack of any comparable arrival lounge in T5 is a deal breaker for me.

PS - DL is excellent too with their arrival lounge. Waiting to see how UA's Polaris will be.