+1 on the Quarter Pounders.
I have them in my MIA Jazz 5. The low end is tight and well defined. Good low mids and smooth top end. I love the sound of these pickups. They are great for rock.
Output of these pickups is massive. My MIA Deluxe Jazz 5 cant match the output of these pickups. I think they definitely have an "active" quality to them. I don't have an active bass with single coils in for direct comparison. Comparing the Jazz 5 with the SD's to when it had the stock pickups in, it is a lot closer to the Deluxe Jazz 5 in terms of "activeness".
I would say that this is because of just how good the low and low mids of the SD QP's is, the massive output and smooth tops. They do sound like single coils though and I definitely wanted to keep that "bite" in the sound of the bass.
I would highly recommend these pickups. For me, they have lived up to every expectation I had of them.