Oh boy...this is gonna hurt to say, because Alchemist is my personal favorite producer maybe of all time, certainly top 3, and he has my favorite discography out of these 3, but...Just Blaze I think is the correct answer here.
Let's keep it hip-hop for a second and think of producer as beat maker. We all know Kanye will go down as one of the greatest producer/arrangers in music history. But he's a Quincy Jones type producer at this point. Even his old beats that he did all himself, usually had very obvious loops and very obvious flips. Very DOPE, no hating.
But Just Blaze is a machine. The guy can do any style better than the best. It's a shame too because I heard he hasn't touched a beat machine in 3 months, and when he is motivated to do music, it rarely comes out. He did 2 or 3 for Roc Marciano's new album, but they obviously aren't on there. The guy is the best producer match with Jay-Z ever, and he was the true in-house producer for The Roc. He's a savage man.
ALC is my personal favorite of the 3. I think no other late 90's "boom-bap" producer has evolved the way Al has. Hell, have any producers evolved the way Al has while still keeping it to samples? The man is a genius, and I enjoy his music the most out of the three of them.
Watch this video from 3:00 on, good mix of unreleased and hits. Incredible House of Pain flip in here and some other gems.