Russel is super fast but most of them are slappy, inaccurate shots as Larry alluded to. To paraphrase the poet Floyd Sr., speed ain't shhhhh without timing. Rigo is not as fast but his timing and accuracy is impeccable.
In combination...russell for sure ..im trying to even recall last time i saw rigo throw a combo
First punch off the trigger i would say its close but rigo more explosive so his punches carry greater velocity
For one punch at maximum speed maybe Rigo is faster. That high speed gives his straight left tremendous power. For all around hand speed I'd give Russel Jr. the edge.