I prefer blackout pickups but sometimes they are just not dirty enough. Of course getting a pickup to sound dirty is easier than cleaning its sound so think about what you want.
When deciding between the two, remember that blackouts were designed for more aggressive styles, they're made to be more thick and growling. Emg707's and 707tw's are more versatile in my opinion, if you know how to work a volume/tone control they can clean up very nicely, then kick on your distortion and they scream. I love my 707tw's, but blackouts are great too. It comes down to whether you play strictly metal, or if you enjoy clean passages as well.
Very true, which give you two options if you do go with the emg's. Either pay more to a tech to rout it, and install them unless you can do it yourself, Or break out the flat-head screwdriver and a rubber mallet
I've thought about replacing my 707 in the bridge with one of those. I think from what I've read the 85-7 is too similar to the 707. Let us know what you think about it if you get it.