Well, I can give you a quick run down, and I hope you get an idea of pickups.
Magnet types:
Alnico: warm, a bit dark, great clean tones, tends to muddy up under heavy distortion
Ceramic: bright, extremely bright with subdued lows. These magnets handle extreme distortion with great clarity, but they tend to be pretty bland. They are also hotter than alnico, driving tube amps more.
Neodymium: Even, full frequency tone response. They tend to sound bright because they grab extended highs other magnets don't grab. Fairly hot and handles extreme distortion very well.
Samarium Cobalt: similar to alnico but without the dark coloration; strong midrange; handles heavy distortion well.
Windings:
the more windings, the higher the output will be and the bassier the pickup will be.
Pole pieces:
the larger they are in diameter, the brigther the tone will be, blades being the "largest pole pieces." Alnico poles give a vintage tone while stainless steel blades are bright and cutting.
Active pickups:
are extremely bland no matter what magnets are being used. They are usually bright with subdued bass and mids. The benefit to these pickups is that they are excellent for extreme distortion as remain exceptionally clear and quiet. But the cleans are pretty bland if you're looking for beautiful.
I think that's all that someone not looking at ordering custom pickups needs to be concerned about (and custom pickups are usually very expensive). Hopefully, you can make a slightly better decision. I encourage you to look past the big boys: Dimarzio, Duncan, Rio Grande, etc.., and look at some of the more reasonably priced offerings like GFS pickups.
