I would most likely put it in something tuned to E or D and I play almost entirely rhythm of the old school thrash/doom/death variety, so looking for something like what you described above, until you made mention of only sounding best in low tunings. Armed with that knowledge, what do you think?
I think it's an amazing pickup for OSDM and thrash rhythms. The lower you tune your guitar, the more modern the pickup is going to sound. Backing the pickup away from the strings will also help that, but I personally preferred it pretty close to the strings for more output/easier harmonics.