I am pursuing my BA, so I'm not a grad student yet
However, I've had several classes with digital textbooks. I print them. Going digital is acceptable to me for reading a book for review or for research. For textbooks, I do not learn as well using a strictly digital format (even those that allow "notes"). It is a learning issue ... plus I have "old" eyes and reading constantly on a computer screen (or e-reader screen) is more difficult and cannot be accomplished for hours at time, as I can do with a paper edition. The learning issue is more important to me than the forest issue -- plant more trees!
That's my 2 cents worth.