No Cowell cramping her style.
Reunion with Lewis Hamilton, so a happier bunny.
No similar judge to compete with - the kooky 'gypsy Paula' Abdul, speaking of universes and often in tears.
Free to be irreverent and say rude words on live TV (but not the f-word, which will see ITV fined pre-watershed). In the US you can't even say bum on TV without it raising eyebrows.
Bigger career here, so better known and more credibility as a judge.
New girl. The new XFUK girl is always feted, like a Bond girl, whereas the one in her second series starts to receive criticism.