I love my AM neck. It reminds me of Petrucci's older lead tone from "Awake," and "Images and Words."
To me the AM neck is nice and full sounding, warm, and drier than the coldsweat. It is also the hotter neck pickup when compared to the HD or CS neck. I love the way sweeps sound with this pickup, too.
I have two sets currently installed in:
1) a mahogany guitar with a bolt-on maple neck, rosewood fretboard
2) Alder body w/maple top; maple neck/fretboard
I prefer the AMs in the mahogany guitar. I will be replacing them in the brighter sounding guitar - that guitar's tone has just a tad too little low end for my tastes and needs a Warpig. :)