I don't agree to the see SD- and conventional ADC that opposite. A conventional high speed ADC will show output noise as well, even the signal source does, so you need to refer to averaging/statistical methods. The chaotic (but not purely random) noise generated by a SD will be reduces to an acceptable level with appropriate decimation filters, so you can apply classical measures like INL/DNL, and SD datasheets usually do. Frequency domain quantities like spurious free dynamic range should supplement it.