Admirals Clubs are also crowded but less so than Sky Clubs judging by what I read online. Surprised that they are more stingy than others when it comes to international itineraries but I guess the credit card entrances explain that. As someone who doesn't fly DL (this is my first flight) I can assure you that the lounge situation isn't much better at AA or UA. I have an Admirals Club membership for solely US itineraries but I'm giving that up at the end of the membership year. I usually get access on AA and UA due to class of travel as well as status.