I just got my first Luke Cage cover! But who should I get rid or, Quicksilver or She Hulk? They both have one cover of two different colors, both still at level 40. Let me know soon before he expires! 
this is pretty subjective and others might have different opinions/orders but I’d order my drops as QS first, then mystique, then shulk. spidey and colossus could make that list too, but you’ve already put some iso into them. but not too much.