I love 'Leave It', but 'Fancy' is much better. It's catchier, its chorus is perfect to sing along to and they did a different vocal arrangement to make her voice sound deeper, which I like.
Anyone voting Leave It is a delusional Charli hater. Charli adds so much to the song, it's a basic song without her. Iggy is great but Fancy isn't that great without Charli.