It mostly depends on preference... if u find that learning via a pdf online textbook is more convenient and easily accessible for u than carrying a heavy textbook around with u everywhere, then use that. its all about what learning style suits u best. i personally for psych used a print hardcopy textbook as i jus couldnt be bothered bringing my laptop to school, then opening it, finding that pdf file, etc. n i advice u, for psych 3 and 4, dont jus use ur textbook solely for notes, use other books and study guides (i.e. a plus atar notes for psych 3 and 4) to guide u when u write ur notes. not everything in the textbook is 100% reliable n accurate n they can often include uneccesary info that u jus dont need to know. so for the most part, i preferred study guide a plus notes over my textbook (b/c it jus had so much unecessary info n these notes just cut that info down into small meaningful manageable chunks, which makes learning more fun, easy and efficient). while i seldom used my textbook for notes, i did use it for questions and some research method practice while i was bored in class or smtn. i jus found questions that were relevant to the study design. anyways, do whats best for u. if learning via a print textbook is more preferable for u than online pdf learning, than dont hesitate to try it out. i got a 40 in psych and i thought it was bcoz i consistently did what i thought suited my learning style n if u do what u feel u prefer to do when it comes to learning, then do that, instead of doing what ur teachers encourage u to do.