I had a 57. For EMG's stuff, it's by far my favorite. Supposedly they are more vintage voiced with more of a PAF feel. I'd agree, but it's a slim margin vs. EMG's other offerings.
While they may not be everyone's taste and the name scares people away, GuitarFetish's new REDactive series is by far my favorite actives to date. I've replaced the 57 and 81's in my main guitars in favor of the GFS's. Running them at 18 volts is even better. Warm but with nice high end, nice dynamics and the typical active clarity and quietness.