I have a set that I haven't used for a while, and I've never installed it in my SG. That said, this is what I can say about the neck.
I think it performs well under gain, at least for single notes. I detest neck pickups generally for power chords but I guess you must be playing stoner rock or something, so I won't say much about that other than to say that it didn't sound worse than the Cold Sweat neck for power chords.
It's a very hot pickup so I found it didn't work well for cleans on my Peavey 6534+ - maybe because I don't like warm cleans that much, and for those warmer cleans like you get in '70s Sabbath the A-Pig bridge can also handle them. I did like the cleans through a solid state Yamaha amp though, they sounded very nice and natural. I just think that the output was too much for my tube amp, which only has 'okay'->'pretty good' cleans anyway