Awesome pickup for metal! I use this in combination with the 85, and i almost every time end up using the bridge pick up in-which is the 81. The sound is really thick and sounds great.
This is the same setup as Matt Heafy from Trivium uses in case you want a reference point of the sound.
I would recommend soldering instead of replacing existing parts (with the included accessories), since i found out it was way easier soldering.
Pros: Killer sound, looks good, much more quiet from the stack when not playing and the volume pot is up.
Cons: It's a active pickup - you will need to replace the battery every now and then