Would for sure go to the Pier. And I'd call it a 10min walk. Ambiance, overall more quiet (Wing is open to the terminal, and to my recollection doesn't have any windows (can't recall, only been in there once)). Wing F tends to get much busier than the Pier F given it is much closer to security, so assume same for J lounge. If you have 2.5 hours of lounge time, the 20-25min walk is easily worth the "investment" in my view, notwithstanding a walk ahead of a long flight is always good.