I used to hate A7X out of ignorance, thinking "Oh, they're just emo-dressed people who will sound like everyone else."
Eventually I bit my tongue and listened to a few tracks off City of Evil. It wasn't the most amazing thing ever, but it was a surprise; I never knew they were so influenced by progressive metal and other 80's metal, whether it was the "underground" kind of metal (Metallica, Megadeth, etc...) or the "pop" kind of metal (Guns N' Roses, and glam metal).
All I have is City of Evil at the moment, but I'm definitely intending to get Nightmare soon, and soon enough once I have any money, some of their other albums. They're a pretty good band, compared to other popular rock/metal bands out there these days, it's nice to see one that can actually put their money where their mouth is and play instruments with talent. Synyster Gates is a pretty great guitarist. Personally though I'd prefer for them to write something in a different key, though, most of their stuff is all the same key.
Just... a few analytics from another musician here. 