Taylor had lightning handspeed that couldn't be paralleled. I'd say he was faster than Leonard overall because of this. The difference in footspeed wasn't enormous.
I certainly think Ray was more Accurate when cutting loose...i dont think Meldrick could of improved on his dismissal of Andy Price for Accuracy, or indeed speed, Also after 12 rounds of war with Hearns the quality of Ray's combinations in finishing Hearns was phenomenal, I dont think Mel had that Ability Long Haul, It might look good to the eye throwing a blistering 6 punch combination, but if on replay 2 or three of the punches are seen to miss or graze..whats it worth.
Taylor was faster. I can't think of anybody in my lifetime who was. Ray had more power and a higher ring IQ.
They say Howard Davis had the fastest ever hands in boxing. Hearns said Davis used to play with him in sparring.
It's the old shoe shine thing: throw 6 punches of moderate at best power or throw slightly slower ones with everything behind it. Pac is unusual because his fast combination shots still have sting. Juan Diaz' don't, but fighters can't keep up and get frustrated. Leonard was fast as hell and maintained pop. Sometimes Taylor sacrificed pop for flashy speed, and throwing a six punch combo leaves you open to some terrible terrible flush counters. Taylor is faster of hand, Leonard was, for all his flash, still amazingly fast and more practical.