But the gain is in the actual functioning of the unit. Thats WHY a user would be buying it.
I'll put it another way...in my experience of both type diffs, the LACK of function from the ATB unit makes it completely cost prohibitive...ie. even if you had to strip a plate lsd every 2/3 years to check/adjust the clutch pack, thats FAR more economical in terms of performance gained versus £costs£.
I cant stress enough how much like a standard transmission they feel (ATB).
I guess it comes down to how serious you are, but imo if your considering an lsd of some shape, may aswell fit the one which works considerably better.