Well, That is a fine question you might ask yourself, considering the legendary Metallica goes up against the underdog-like Iron Maiden.
Metallica
Pros - My 4th favorite song is Fade to Black and i can play it on guitar!! - They HAD Cliff Burton (R.I.P) - James Hetfield has awesome vocals!!
Cons - They kicked Dave Mustaine (sucks for them because Endgame basically owns any album my Megadeth and Metallica) - Kirk Hammet thinks he's so cool when he's really obnoxious - all albums past the ..And Justice for All sucked.
Iron Maiden
Pros I dont know them They were on Guitar Hero 3 and 2!
Lets face it Metallica has so much talent they could play "Twinkle,Twinkle" and people would buy it. Just raw energy at its finest. Yet Maiden writes very catchy lyrical tunes. But its still metal comared to rock. So I'll take Maiden.