Gotta +1 this one pretty readily. Boarding is great on both metals lately - breezeway basically works as expected and I never have to wait very long to board. Especially now that I have a sky club membership, if I have a confirmed F seat I often show up a few minutes into the boarding process (hey, the club has Alaskan Amber

) and can really easily jump line and get to my seat without any hassle.
I never had really thought about it until I flew on an AS codeshare, where they seemed to board by "back half of coach" followed by "front half of coach". This caused a mad rush to board with lots of crowding, while with DL zones the crowd would have been much thinner.
Breezeway/boarding definitely did end up with best of class, for once. ^