I see less banding on my 7D than on my 5D MkII (and much less than my 40D had), although overall, it is noisier. From the short test I did with the 5d MkIII, there is a significant improvement in high ISO noise, perhaps a stop or so. However, I tend to slightly overexpose and rarely have problems with banding on my 5D MkII at low ISO. Any shadow noise is usually minimal and irrelevant in print, the exceptions (apart form when I've underexposed) is in long exposures (i.e. 20+ minutes), where most digital sensors start to get problems. It's probably one area where film is still better in terms of overall image quality. Some of the noise is due to heating up of the electronics, so there is an argument for boosting the ISO and reducing the exposure times.