I really enjoy Spider-UK. He is similar to U.S. Agent: costs 3, has 5 life, and has a retaliate effect.
If you are willing to include other Web-Warrior, Spider-UK can becomes the deadliest retaliating Ally in the game. By simply being a Web-Warrior yourself (Miles or Gwen), he deals two damage instead. With a full suite of Web-Warriors, you could be dealing 4 damage every time Billy defends.
Regardless of the number of Web-Warriors you have, you'll likely get two full Villain blocks out Spider-UK. Additionally, as his ability is worded "When Spider-UK defends against an attack" as opposed to Relatiate, he will deal his damage even if he is defeated.
You can build around him as a minion wrecker, or simply use him to weather attacks, Either way, you will get your value out of Billy Braddock, As a Web-Warrior, he can be the target of Across the Spider-Verse He helps utilize Silk's ability. He can be readied by Spider-Man (Peter Parker). He contributes to Spider-Man (Miles Morales) 3 Web-Warrior requirement.
I rate Spider-UK a A-class card: With no specific building, he is good. In a Web-Warrior build, he is very powerful.