I ride with a guy rockin' DT's on a RB2... indeed, he must anticipate his shifts to an exponentially greater degree than me with my brifters. He also has to "break position" to shift. Doesn't stop him, but it does mean he's often a gear off from ideal, and those are his words. Also, if you like to climb, with brifters you can easily switch gears (2 gears, actually) when going from sitting to standing, while in the motion of changing position! Again, when climbing with my buddy he is typically not in the ideal gear if it's a climb that is long enough that there's some sit/stand switches happening. So he's generally mashing harder than ideal while sitting.
My conclusion? Brifters are better. Then again having done thousands of miles with this guy, clearly DT's work. Just not as well.