After watching the X Factor performance I started thinking people here tend to shade every one of her live performances too much, including myself, talking about her lack of vocal abilities and making fun of her. We all know songs like "Firework" don't fit her voice range at all and she may be not the best singer but she's a pop star taking orders from her label.
She has no choice. She's not a Britney Spears who can decide which song to record and which one not to. She's not a Lady Gaga who can write ALL her songs. But that's how things work, in her situation, unfortunately, the singer is the last piece in the puzzle.
I don't like her personality, I just listen a couple of her songs, but if she takes the challenge to sing live and give her best no matter how bad it sounds, no matter how out key she is.. she has my respect and the "The one that Got Away" acoustic show proves me that she has a really good voice.
Well said though 
