First of all, I respect the purpose of the song and like the original it has a good heart. The problem is that some of the artists did not take this song seriously or tried to add humor where it isn't wanted. The biggest offender was Wyclef Jean. He disrespected the entire purpose of the song and made inappropriate comments through the song such as "Nous ce monde là" in a unneeded crazy voice and said an inappropriate "Cabarett" in a scream right after the rap verse. But probably the biggest insult to the song he did was right after the song got back on track after the so-so rap verse. He sung "Haiti, Haiti, Ha, Ha, ha" repeatedly. In my opinion, that one sentence mocks the entire purpose of the song which even with his earlier contributions and the rap verse was still ok. Jamie Foxx also did a bad Ray Charles imitation which seemed to insult more than compliment. The other singers were alright and some even had really good voices, including people as diverse as Lil' Wayne, Pink, Tony Bennet, and Mary Mary. The rap was better than I thought. What it really comes down to is Wyclef Jean and how it pales compares to the original song. If there is a disaster and this song ever comes out and you can't buy the original, make sure you ask for Wyclef Jean to be removed even if the price costs much more. If you take him out this song would get knocked down four age levels and if you took the Ray Charles imitation off, it would get the positive messages tag added on.
PS: Just before you say I forget, I thought Bieber was better than he is in some of his songs but he would have been even better than that if his voice was deeper. Michael Jackson probably shouldn't gone in the song only a few months after his death but it's nice they thought of his legacy while writing this.