Christina Aguilera’s impersonation of Samantha Jones is astoundingly good. So good, in fact, that she’s been asked to perform it on camera more than once. But doing a perfect Samantha Jones appears to be where her talent for celebrity impersonations ends, because this “digital exclusive” filmed for the finale of The Voice is filled with Aguilera’s less than perfect versions of Britney Spears, Miley Cyrus, Sia, and, for some reason, Cher.