This song has the distinction of being the first ever song I have ever paid for and downloaded, as I fervently hate Itunes and the way they want to control your music. It is also significant because I have never liked Leona Lewis, but this song has just grown on me. I know nothing of the original version, and I have read and heard the comments about "ruining it" but if that is true, then let her ruin a few more because I love it.
As for the site, I have had no problems at all - people who complain of slow downloads etc must have something wrong at their end. I can see myself buying a lot of stuff on here.