Basically if what you want to do is charge in and cause carnage dont take WOC and take demonic speed. For that purpose it is better.
I don't agree with that.
Remember that we are talking about city fight (and it also holds for other times as well). But if you want to jump from cover to cover so you don't get shot up. With speed, you can move as little as 7". If you are trying to cross a street, or get to the nearest piece of terrain for cover so you can hide your
DP, and it is 10" away, you can make it easy with D. Flight, but if you roll badly with your
FoF, you can leave yourself open to a world of hurt.