Best Rank For MCI?? (Apart From Mayhem, and Mayhem+)

Hi, I would like to know what the best rank for MCI is, apart from Mayhem and Mayhem+, I am asking this because I could consider saving up for a new rank, what would get me the different mobs/infected, and how well it is for i'ts price.

Thanks for reading my thread, and I hope to be able to get a new rank in the future.

-CheesyKitty

P.S: I am currently Spaz, so it would be spaz --> ____ (the other rank)