Probably Hearns then Leonard.. No matter what, you were always going to get an exciting fight out of Tommy. The fans got their money's worth just about every time the man stepped in the ring.. Sugar is not far behind though, and in fact has my vote as the "best" of the fab four. He was quick, methodical, could take a punch, give a good punch, and had an excellent work rate.. He was also classy and yes even came across as being educated. He also beat the best of his generation, regardless of what some may have thought of some of the verdicts.
Hagler was a great champion Hearns could hit and climbed weights well and went to war with Hagler and Leonard Duran was just a boxer at heart fought many decades at many weights and was just a great person Leonard was just an amzing guy to watch and could do so much
I grew up idolizing Leonard. Liked Hearns a lot too, and still do. I've always respected what Duran could do, and have an even bigger appreciation for him now. Both he and Hagler had a stranglehold over their respective divisions. Hard to pick a favorite really, so I'll draw a card and say...Hagler. I love those MW maulers.
MARVELOUS MARVIN HAGLER - Beat all the other three in my book (scored it to him by one round against Leonard by the way - and would've won it by more if he hadn't been fighting orthodox for the first 4 rounds aswell) after him (if we're talking my favourite) then it would have to be Roberto Duran, then Tommy Hearns and then Sugar Ray Leonard Hagler was the man though