my school uses windows on pcs officially. i know the students that i've talked to with macs complain that they have a hard time finding a mac on campus that they can print from. another girl in one of my classes last semester was on a mac and when she submitted her papers to our professor, she lost a TON of points and almost failed the class because Pages couldn't format correctly when opened in Word. the professor thought she was slacking through it and not using the proper formatting, but really it was just her word processing program messing with the way Word reads files.
those were points she shouldn't have lost. i'd find out what your school uses mostly and go with that. you don't want to be stuck with something like that girl in my class had.