Rules update: as of Mutant Genesis, permanent cards can no longer be blanked by other cards that aren't part of their "set." So Vivian can't blank the Infinity Gauntlet any more.

(She's still got a lot of great uses.)

All you need is Vivian plus Make the Call/Rapid Response and forget about the nastier attachments in the game, like Sonic Converter, Solid-Sound Body, Vibranium Armor and Upgraded Drones (just to name a few).

But what puts Vivian's ability in another level is to negate the Infinity Gauntlet: as long as you can play her again and again, forget about the most powerful weapon in the entire game! (This alone makes Vivian the best ally in the whole game imo.)

And if there aren't any nasty attachments in play, you still can deny nasty effects on non-elite minions and side schemes.

The fact that Vivian is a basic card without trait restrictions is the cherry on the top.

And, as if she wasn't good enough, she provides you with 1 threat removal and one free block. What's not to like?