I saw a Skyteam member(which would be on zed) listed for DL op'd INT flight that had plenty of seats in business and few in coach. All nonrev's got biz except one pair (probably a child/parent?) and Skyteam pax had coach. Flight left with over a dozen business seats open. The 2 NW emps were up front along w/buddy pass riders. Just an observation--AND--I agree, Delta business class is awesome!