Whether the type of light or the exposure is more important would be a pretty hard argument to win no matter which side you were on. Plus, why argue? Let's just learn it all and learn it well. How you expose your images can have a massive impact on how they turn out and how much you can alter them in post without losing quality.
When shooting digital, I always spot meter for the brightest skin on their face (usually the cheeks) and underexpose just a tad. The reason I do this is because if you accidentally over expose something with digital (also known as "blowing it out"), the detail in that over exposed area will be gone forever. So sad. Don't let that happen to you. If you over expose skin, that means that normal human skin texture won't be able to be recovered in post. On the other side of the spectrum, you are able to bring back shadows a pretty surprising amount so you don't have to worry about that too much!
Film reacts pretty differently to over exposure. Instead of losing overexposed detail, film actually retains it pretty well (even when over exposing by 2 stops). When I shoot film I'll err on the side of over exposure instead. That also tends to give it a softer, more muted look. Unlike digital, film tends to lose the details in the shadows more easily.