i think sensitivity preference has a lot to do with physical orientation to the device.
I feel ~3200 is my sweet spot, but i'm also a tip gripper with a sub-optimal desk/chair setup, which results in a low-motion wrist-anchor control style being the most comfortable for me. I can't do palm or claw, because it would require my surface to be lower, which doesn't work due to fixed-position chair arms... and i feel my chair is already too high, because i like a firm flat foot grip of the floor, which i can't currently do, because then the desk surface is too much higher than the chair, which ends up putting all kinds of strain on various points.
If i could lower my chair to optimal height, and then also adjust my surface to the optimal spacial relation to that chair position, THEN i would feel comfortable with a palm or claw grip, and low sense high motion control style, since i wouldn't have to anchor anymore, in order to remain comfortable.
But for now, there's just no way to make a high motion control style work, because it would require bizarre arm positioning. Plus, i only have a 1920x1080 24" anyway. 3200dpi works pretty well for being fast enough for macro, slow enough for micro (though i've noticed micro is just irritating no matter what, with my g700... mostly because the sensor is at the front, and i tip grip...)