Best of Comps: 2nd or 3rd generation tapes....

I have heard that original comps such as Neil Yound "Decade" and the Stones "Hot Rocks" often used inferior master tapes...is this true? I have the Stones...and granted they were never an audiophile band... but the collection sounds very muddy...any other collections to avoid? Any that sound good? Dylan Biography? Neil YOung? Jethro TULL Moody Blues?