You and Haymitch are all like... <iframe width="420" height="315" src="//www.youtube.com/embed/_gqVVQ-q8Zs" frameborder="0" allowfullscreen></iframe> For real though, I agree that I can't hear anything new in this A7X outfit. At their best, they sound kind of like Dio's solo band (e.g. Holy Diver).
Wow, you pulled the exact song I used to help my kids sleep at night out of thin air? Kudos, my friend.
So, personally I like Avenged more than Metallica. Avenged, to me, sounds like a modern take on Judas Priest or Iron Maiden with the dual guitars, melodic choruses, and cheesy satanic schtick. However, this comparison is kind of ridiculous as Metallica is probably the most significant metal to come along since, well, Judas Priest and Iron Maiden. They are like the Zeppelin of metal. So I voted for Avenged but it's not really a a good comparison. It's like asking what's the better classic rock band: Led Zeppelin or Cheap Trick.
Whether it's a generational thing or not, I'm 19 and A7X is a bunch of ****. Metallica all the way, especially those first 5 albums.