Difference between driveshaft one-way and oneway diff?
 

What is the difference in performance between the two?

here are most of the variations of one-way systems for off-road

one-way layshaft
this will let the front diff free wheel under braking and therefore the front wheels, however, the 2 front wheels are still connected via the front diff, so you would not get as much turn in as with a diff/driveshaft one-way. you would obviously only get rear wheel brakes
there are also limited slip variations of this, think of the clicker for the xx-4, this allowed you to vary the amount of brakes going to the front wheels.

one-way unit (Losi xxx-s/4 style)
this will let the 2 front wheels spin independantly under braking, as they are not connected via the diff under braking then you get loads of turn in. on power there is no diff action, just a solid axel, this gives loads of on power steering as the inside wheel does not spin up(diff out) when in the air. again, you only get rear wheel braking

one-way driveshafts (normal diff)
they work the same way as the losi one-way unit off power on turn in but on power still has a diff action so can loosed some on power steering. same as all the others, only rear wheel braking

I think that is about it, there may be more, there may be some variations of the above.

hope that helps