I never used OS Giken Super Single before, but using the Ogura Super Single.
The main benefit you get from this is the flywheel supplied normally are very light giving u faster acceleration and deceleration as well the very strong and immediate grip when you dump your clutch.
Before i used these super single clutch system i only used exedy 3 puck type, and once i used these super single system, i don't think will go back to 3 puck type.. Power transfer to the wheel is so much more and faster, it felt like it had less loss of power to the wheel.
Disadvantages is its noisy with the cheng cheng noise but some people like it, haha..., and the pedal is heavier..
Advantages is more direct power transfered to the wheel and faster and they last quite long. Used it for one MME race, about 6 sunday practice and 3 MSS race. Clutch system still good but change the cluthc bearing once last month.