Nacho churns out consistently good Fighters, but make no mistake, he's not the guy who taught Juan Manuel and Rafael how to Box. From Rafael's own words their Father is largely responsible for their skill levels, while Nacho's Chief role is their conditioning.
By his own words, Jesse never trained Orlando, just Gaby. But don't forget Lamon Brewster for the 15 seconds he was a wrecking machine, against Golota and Qrazniqui.
However, Jesse's not much of a strategist. You should know this. What he does is similar to what Lou Duva was known for. You'll be in SUPERB condition, and he's the biggest cheerleader for his Fighters ever. He even cheers his guys on with encouragement for a single punch they land in a round of sparring. "THAT'S THE WAY TO WORK THAT RIGHT HAND!!"
Most knowledgeable?
I'd have to say guys you don't often hear of. The most famous would be Freddie Roach, because he understudied Eddie Futch. Eddie and Bouie Fisher are the old school Elite IMO.
Kenny Adams and Dan Hause are BRILLIANT Boxing minds. If you click with him, Floyd Sr.'s an excellent trainer in all truth. He's one of the guys who is a better trainer than he was a Fighter. Eddie Mustafa's a good trainer who tap-dances the line between cheerleader and strategist. One thing he did excellent in the Dawson/Johnson fight was TELL Chad his second wind was kicking in. Not ask him if, but TELL him.
John David Jackson's a good trainer if one listens to him as well. Boza-Edwards is a good trainer in-terms of Boxing strategy as well. If Sam Peter saved himself by out-boxing McCline after the initial debacle in that fight, it can be attributed to Boza more than anyone else.