I heard it many times now and I honestly have to say that I don't remember a better single since "Infinite Dreams" (1988). On a sidenote: I also liked "Futureal" and "Rainmaker" a lot, but "Breeg" might top these for sure.
Some people complain about recycled ideas, but the only thing that Maiden might have done before, stylewise, is this kind of intro. Still, its melody is new. The rest of the music is very fresh and new for Maiden, apart from a very short part in the intersection (during the harmonies) in which the rhtyhm guitars remember me a little but of "Look for the Truth".
And what a solo by Dave Murray ! This is one of his gems and I am pretty sure that it's worked out well (like Adrian often does) and he will probably play it live the same way, as much as he can.
My favorite parts is by far the chorus though. Great vocal lines and a very catchy vocal melody and nice chord progression, which stay in your head constantly.
I also love the "marching" drum beat, especially in the chorus (again!) when I hear the ride cymbal, bass drum and snare combination, making it impossible for me to not move my head and feet.
Simple but so effective! Way better than e.g. Nicko's not well chosen and messy drumparts in "I live my way".
IMO the mix of this single (and album) is the best sound Maiden has had since The X-Factor. And it might even be the best mix of all albums, but this is something that has to be judged after we will hear the new album.