FRED is becoming one of my faves. I use it in the bridge position. Great for both rhythm, and lead. For leads it's got this warm neck pickup type tone, with a screaming lead tone mixed in. Notes just seem to want to sustain. Don't know how to describe it really, but I like it.
I guess most don't think of it as a "metal" type of pickup because it's so closely associated to Joe Satriani.