I do own the Painkiller and although it's said to be "ice-picky", from my experience that has nothing to do with the highs which I find to be present but balanced. The focus lies in the high mids and the pickup has a very grinding nature, perfect to cut in a mix and hit you in the face.
I had it in a Jackson Fusion Pro first, that guitar is rather dark in sound due to the shorter 24.75 inch scale (I read from your description your Kelly uses the shorter scale as well?) and its Mahogany Body in combination with a Rosewood fretboard. The Painkiller had a huge but tight low end in it, although the mids drowned the highs a bit and that was the reason for me to move it into my Jackson DK2M Dinky with an Alder Body, Maple Neck and Fretboard and the longer 25.5 inch scale. Now it's quite middy yet balanced, tight lows, no overbearing highs, very clear on chords and a rich and fat saturation overall.
Now I have to clarify some things: I have the Painkiller with Black Battleworn covers and hex screws, so this might contribute to the enhanced low end I found in it, don't know how much regular nickel screws would behave when compared. However you always have to consider your amp, your cab and the voicing nature of your guitar, my Jackson Fusion is dark and has somewhat similar specs to your Kelly which doesn't necessarily mean they'll sound the same.
As far as the bands you mentioned go I'm a very big fan of Revocation and the Painkiller should get you close to their sound. As said it isn't the smoothest pickup but will certainly get you where you want to go. And aside from that, why get another Juggernaut when you already own one? ;)
Cheers
