Seymour Duncan SM2 vs. SM3

SM2 was a little louder. Sounds like a small output bump over the SM3

The SM-2 had a bit more clarity and High end to my ears, making it more articulate and more "single-coil-ish" while the SM-3 was a bit more "smeared" sounding, but in a warm and pleasing way.

Same

SM2 sounds a bit tighter while the SM3 sounds less compressed. Both of them sounds really good and I can't really say which one I would choose if I bought one new. I have a used SM2 waiting for my tele to be finished...

SM-2 had more bite.

I like the granularity in the breakup of the SM-2s, and I like the clarity in the way the SM-3s cut through. I'm guessing the SM-2s are a little hotter.