You have to pick:

Is this one of those infectious zombies where the moment its teeth penetrate your skin you're doomed? If so, very few options wouldn't beat this.

Would I gain a power or would I just be a member and attending all the luncheons?

Or, perhaps, become one of the existing members (eg Wolverine, Cyclops, etc.)

You'd have a power (you can't be a member otherwise). The power would be on par with a typical x-man.