Re: DiMarzio Breed = The Secks
I have a Breed neck in a 24 fret basswood RG, and I think it's great in there. Whenever I try the Screamin Demon in the neck (with two rows of allen poles) it hits the same nerve. I'm not saying they're totally interchangeable, but if I have Duncans in the other positions I would use the Demon to match. I won't change it, but if I sold the guitar I would just use a Demon next time because I have a couple.
I have my Breed neck with a Super 3 in the bridge, which is a scorcher. While it doesn't sound "like" the Breed bridge, it's very loud with a highly "oppressed" top end, and in that way they are alike. I do (as others have mentioned) consider the Breed bridge as a "fix" for a brittle sounding guitar. It kind of has a "250k pot" effect, but localized to that pickup. So if you split to single with a middle single coil, it brightens up nicely.
Personally I'll always tout the Alternative 8 over the Breed, just because it has top end presence where the Breed shaves it off.