I have it and got it for the same two people you just mentioned. I have only watched the beginning, because my friends got kinda bored with it. I can't really speak for it because I haven't seen it the whole way through, but I thought it was boring.
I have seen it. I didn't think it was that great. Besides the two known singers, everyone else is a little on the tone deaf side. And the lyrics are far from creative or interesting. Its a cool concept but I would possibly say rent it but don't buy it.