Nightwish's version of this song is obviously far superior and it is apparent that both Edu and Tarja are out of key. Apparently from metal gossip on YouTube, they were both mic'ed up very poorly and could not hear the music well at all. Well I can actually see that, but Edu's singing is just not very good here at all. I actually like his voice with the band normally, but he sounded very course and rough at this concert. He must of had a rough night because he even sang Angra songs very poorly as well. Here is a video of Angra's setlist in Rock In Rio 2011:
If you look up any Angra live video besides RIR 2011, you will see that they are normally a very good live band and that Edu is usually an excellent vocalist. I myself find them to be one of the best live power metal bands around, and this performance actually shocked me. We all have bad days and experiences so rest assured that Angra is still a very good band but had some issues that day.
So yeah, this is not a very good version of POTO.