Simply Brilliant Action and Art
Every character is on form, every villain is interesting and nuanced. The Colonel, while he tries to stay an honorable fighter, falls back on tricks and does everything he can to win against Captain America. Dynamo is shown to be an unstable murderer who was only kept in check by winning, Loki reveals himself to the Ultimates, and the Syrian speedster is ripped apart by Quicksilver. Tony Stark unveils a surprising new Iron Man, which I love Millar wrote in. It's hard to do new things with Iron Man, but Millar always keeps us on our toes.
The rest of the Ultimate universe gets in on the action too, which works out phenomenally, and opens up Hitch and Neary to do a stunning two page piece of art that I love. Speaking of 2 page art though, this issue has no less than four great art pieces, not including the phenomenal cover and wraparound art.