I am flying back to SFO so I need to clear customs and immigration at first port of entry, meaning Houston, Miami or LAX for UA, Delta or AA. I have Global Entry so immigration is nothing to me but I need to and hate to claim luggage and check back in again. I've done Polaris out of SFO to Asia and not impressed with the SFO Polaris lounge or seat, I will take Qatar QSuite over Polaris anytime. So I will take Copa and spend couple days in Panama City. Also, for the person about penguin poop, I've been told they would hose off whatever you need and you can keep them in the mud room, no need to bring any outerwear back to your room. But bottom line, D2D is not a good deal unless you can dictate what route you want on the first go, even that, it is at least a few thousand dollars cheaper if you book your own, speaking of Business class in my case only.