Jones was significantly faster on his feet and had much better reflexes. This would only be a debate if we were talking about handspeed only, and in that case I'd give it to Mike, but when you factor in all-purpose speed it's a wash imo.
Pound for pound, I'd day Roy Jones, especially factoring in handspeed and footspeed with relation to his power. Jones' quickness generated immediate power due to the fact that his punch follow through was fast. Mike Tyson had very good speed and power, comparable to that of Ali and Floyd Patterson, strictly hand speed. Tyson has more overall power than Jones at prime, but on the basis of weight division, nobody was faster than RJJ.
Remember Jones-Griffin II? Jones had no lack of power at LHW, he just preferred dragging his fights out and clowning his opponents. I remember George Foreman saying after the fight that Roy easily had enough power to go to HW.
Tyson as jines mainly relied on speed while tyson used speed to get in close and power to KO people wen he got there.
I think that in terms of combining blinding handspeed, and devestating power, no other fighter in history had it like Tyson. The 85-89 Tyson literally had the handspeed of a middleweight, and no need to even comment on his power. The 160-168 Jones comes pretty close, but I defenitely give Mike the edge.