DS, he was able to beat Flash when he took on the JLA. Unless this is after HOM in which case I think DS still wins unless QS is faster than Flash now that he's faster.
almost all the feats slade has everyone wants to call them PIS cause thye probably just dont think he should be able to do all that stuff, lame, but anyway he did keep up with kid flash for a few seconds while running then hurt him and he IS able to see people at flashes speed while there running and thus can hurt them, QS is no where near flashes speed.
I don't have the same opinion; Flash should've been fast enough to hit Deathstroke even BEFORE the explosives went off. He's fast enough to K.O. Deathstroke and run all the way back before the explosives even go to effect.
And he sees things in slow motion, Flash totally should've saw that sword for an eternity of microseconds.
the comics day deathstroke can see people who move that fast so its not illogical for him to have done something about the flash or wally and he hasnt done it only one he's done it maybe three or four times.
The argument that Wally JOBBED in that fight with Slade carries MORE WEIGHT, since its pretty much a GIVEN for almost any type of scenario that the Flash(es) has to, no, NEEDS to JOB to make things interesting and end the fight in less than a second.
The writer doesnt even have to use Slade's jobbing aura to get the effect.
its also said that Deathstroke's reflexes are as fast as the flashes, and for your info thats not that hard to get if you knew that he once ran with wally for a few seconds and shot him with his staff.