On superbit dvd they take off all the extra crap and use the space for improving the picture and sound quality, Superbit uses a high bit rate digital transfer process which optimizes video quality. Superbit DVRAB are encoded at about double their normal bit rate.
I buy superbit if i can coz Im not really interested in features Id rather have a dts soundtrack over watching the director trol on how he used the camera or somthing. but the only problem with superbit is only Sony films use it and it takes films a while to come out in superbit.