I wont be using a metal gearbox or injection molded parts like the titan, since they are too heavy, expensive, or both for my application, so I'll have to consider the backlash of printed gears. That being said, the quality and backlash of gearboxes varies a lot based on manufacturer, and a couple of degrees of backlash, which is negligible to a human hand, is several steps of the motor.
Also, that reliability is important, if you're running at 100+ mm/s and your filament is slipping even let's say 5-10%, that, to me, is lost precision. if your motor changes e steps based on the speeds due to slippage, you no longer have a precise (or accurate, if you prefer) extruder, no matter how geared down it is.

My main question left, though, is still which extruder (geared vs not) can push plastic through an extruder faster. I suspect it is the geared extruders because as you say, an extruder doesn't push the limits on the motors speed, so the added torque is likely more beneficial than the loss of top speed which you wont end up reaching. I know the power rating of the heater cartridge in the hot end also limits your extrusion rate, but lets assume that's a non issue.