While I don't disagree that at least from outward appearances the DL One seat would have an advantage over UA's Polaris seat, DL has yet to install it and not sure they even have shown a prototype (other than it seems like they did at the Expo).

The suite with a door concept is nice...but let's be honest the bulk of their fleet is still going to be 767s which probably won't see this seat and other than being installed on A350s as they are delivered, DL hasn't published a timeline for retrofit for A330s or 777s.

I guess what I am getting at is that people can sit and dog UA on installing a high-density configuration and that the DL One suite (with door!) is superior, UA will probably have Polaris retrofitted on the majority of their aircraft before DL has the DL One suite (with door!) on even 1/4 of their fleet.