Hooo boy, what a big question!
Here’s the elevator pitch: DCUI Ultra is a wonderful new membership tier within DCUI. Ultra members have shorter release windows (1 month instead of 6), and access to some pretty awesome DC/WB content. It was just launched days ago, and we’re busy ironing out some issues, but otherwise very stoked!
Here’s the long answer: DCUI ULTRA Tier: Community FAQ 