In my opinion, 7 strings are incredibly versatile - in theory. In practise I've found the neck too thick to do much but chug away at it, as the strings are further apart so it's even harder to play as a 6 string...and for that reason mine is still sat on the shelf (well not a shelf, but you get the idea).
I thought I'd use it a lot when I got it, but I don't...But actually now I think about it, the biggest reason I don't use it is the cheap epiphone pickups :lol: Unfortunately I can't afford BKs for it right now, but the stock pickups are really weak - and you can hardly hear the bridge pickup at all - not the best on a guitar made for chugging :P