Keep in mind that digital cameras' ISO sensitivity has not always met the same criteria! For example, early Canon dSLRs had ISO 100 sensitivity which was deemed closer to ISO 125 by testers. Later, Canon made newer models have truer ISO sensitivity, so rated ISO 100 behaved closer to ISO 100 expectations.

At the same time, even film ISO's were a bit variable. For example, Velvia was frequently rated ISO 40 by users, though the box stated ISO 50.

So in comparing one with the other, how true are they both?!

Generally I find that digital ISOs generally are like using film ISOs typically, in terms of needing (or not needing) to tweak ISO values set in the meter vs. accuracy of apertures and shutter speeds (both of which add their own variants!)