Britney Spears' two-year Las Vegas residency launched Friday, and the reviews aren't as terrible as one might imagine, though they're certainly tempered by reality. Piece of Me is "so winning that it barely needs Britney at all," Jon Caramanica wrote. "Magical things are happening all around her—ornate sets, clever video displays, fiery dancing — but Ms. Spears is there mostly to activate memories, to be a souvenir for the eyes. Rarely did the voice booming out over the speakers appear to be coming directly from Ms. Spears’s mouth. Always a notch or three less committed than her backup dancers, she was at times downright listless."