Tenhou is correct...speed in and of itself is not valuable. If all your teams are 800 speed you'll have the same problems with some maps as you would if all your teams were 300 speed. High speed only becomes valuable relative to the speed of your other teams, so for some maps you'll want all the same speed, for some maps you'll want some speed disparity but not too much, and for some maps you'll want a large speed disparity.