In my LFR campaign, I play a Centered Breath Monk and my friend plays a Brutal Rogue using daggers for improved hits. We are the only 2 strikers in our party and we have only played 3 adventures so far (our party is lvl 2). We both decided we were going to track our stats to see who did the most dmg including dmg per hit as we have been having this debate as well. Our group feels that my Monk is deals more dmg than his Rogue does at this point in the experiment.
My personal opinion is that at Heroic tier, the Monk will continue to deal more dmg. I feel the FoB power dealing static dmg every time I hit is favorable to dealing sneak attack dmg only when you're granted CA. We try to flank every opportunity we can, but it doesn't always happen.
Now, Once we reach Paragon lvl, I'm thinking we might begin to see a difference. The Rogue can add an extra die to the dmg, not to mention taking a feat to increase the dmg die size. So at paragon lvl, he could be dealing an extra 3d8 sneak attack dmg while i'm still dealing my base dmg (5 points currently at lvl 2) to up to 2 creatures. At that point, I feel that the Monk will continue to deal an xtra 5 to 8 dmg per turn (assuming 1 target every turn) while the Rogue will start to out dmg me by dealing 3d8 dmg from sneak attack. I have taken the Pointed Step Style Feat to grant my FoB range of 2 squares. This obviously isn't increasing my dmg output directly, but it may allow me to be more effective at paragon lvl in targeting a 2nd target.
So to summarize, our party feels that the Monk is out dmging the Rogue at this point but we intend to track it and see.