I've used emg 85 for about 2 years now, In all my guitars, and it's best pickup for metal/rock I've ever used!
I got 2 caparison angelus guitars, 85/89 in one and 85/60 in the other. They don't sound the same at all!
And I've used it in alot of other guitars too, And as James said, They are more accurate en enhances the tone of the guitars to the better.
With passives you have to find a certain pickup for a certain guitar, but emg's sounds good in most guitars.
Just my personal experience!
By the way, Don't think the emg 85 sound anythiong like the emg 81!
People who tried the 81 and dosen't like it seems to think that all actives sounds like that.
The emg 85 is clear, accurate, warmth, rich, tight, and open and heavy as hell! That would be my desciption of it