I am a metal man myself, i have an ESP H-207 and my ESP H-307 is on the way. Bloody things are hard to come by, and expensive. Oh well, I find playing the 7 string absolutely no different from a 6 string. it functions the same, does the same thing, has no fundamental playing differences except another string to let you flush your musical ideas out on.
Just more low end for the rhythm guitars. or another string to sweep from. Ahahaha, sweeping all seven strings is a bitch but fun.
