Speed, Great hand & eye cooridination, timing, reflex, underated power- not great but as Maidana said-repectable, then add on his ring IQ (adjustments), he is about as close to the total package as one could have.
Then add on his defense, he can roll with punches, he fights from angles, turns, pivots, twists, giving his foe little to hit cleanly, and when they do land...how many fighters in the history of the sport has gone 18 years and never dropped? on his back or a knee...in 18 years?! if that isnt an underated chin, I dont know what is.

Oh and a shrude negotiater on who he picks to display his talents and skills and when...Floyd has the greatest career in boxing. His resume is TBE.

BUT...that doesnt make him the greatest boxer.