Not bad! But definitely not good either. This just shows again Leona has not a versatile voice, way below true greats level (Mariah, Whitney, Celine, etc). Those people can sing anything, even if they have to completely change it or whatever, they won´t dissapoint, cos they have the musicianship (and the voice of course). That said of course Leona Lewis´ voice is 20 times better than Rihanna´s. We are used to listening to Rihanna singing this song so it´s normal that any other singer sounds weird while singing it at first. But I remember when the song first debuted how I was thinking Rihanna didn´t make the song interesting, maybe the first verse, but then the song kept the same, didn´t grow further, she was struggling to sound interesting in the song to me. After the crazy radio support she always gets, of course I ended liking the song from start to finish. But that´s it. Rihanna, her voice and her songs are not a killer, deal with her basic artistry once and for all. Can you guys imagine Rihanna covering Leona´s songs? Hmm just NO. *plays Hero by Rihanna* lol