I am guessing that they were a cleaner pickup than the Super Distortion you're using now?
Can you help me out here and explain a few differences you've noticed since you've used both?
I find the Super Distortion to be cleaner and more defined actually, and a bit hotter which is what I was after.
Here's a description of Pearly Gates straight from Duncan's site...
Warm, slightly-hotter-than-vintage humbucker. Great for blues, classic rock, southern rock, jam, and hard rock.
Originally designed as a recreation of the pickups in the '59 Les PaulŪ Standard that defined the raw, rebellious sound of Texas blues-rock. The Pearly Gates is sweet, but slightly rude, with great sustain and a bright top end that make harmonics jump out of the guitar. Comes with four-conductor hookup cable."
I didn't find the sustain or harmonics all that great in the bridge position of my Strat which is why I switched. Still, I think the Pearly Gates are nice pickups. This one just didn't do it for me in the Strat.