I've had one of these in my guitar for about a year now. It's taken me this long to set the thing down and write a review.
First, being active, this pickup is HOT- meaning there is a TON of output. With the volume pot on full, the 57 retains that signature fluid EMG compression, without being thin like the more common 81.
Second, even on full the 57 is ridiculously responsive and dynamic. I am a huge fan of pickups (both passive and active) that clean up/distort depending on pick attack. It EXCELS at glassy cleans to midgain early metal raunchy goodness.
The only complaint I could see one having is the sheer output. People seem to forget volume and tone controls are there for a reason. Use them. Play with them. Discover new tones. When I back off the volume to between 4 and 7, all compression stops and the tone opens up wide as the grand canyon. Clarity and punch across the whole spectrum, while still being full and crunchy.
This pickup is a case of something that is new and different, and also very, very good.
Again, it's hot. So my advice to you is to back off the gain a tad, roll back the volume, and let your pick attack get you where you want to go. Response is where this pickup shines, in my humble opinion anyway...