Yes definitely get facebook for uni. It's useful for before uni so you can chat to other people, see who's in your flat and see what events there are. But it's most important for when you're actually at uni and you can all add each other and keep in touch and invite people to events. If someone's having a flat party they're probably not going to remember to invite you if you're not on their facebook. Events are mostly advertised on facebook as well, including socials and events at actual clubs so it's the best way to find out what nights out to go to. Your accommodation will also probably have a fb group or group chat where people will post things. It's a good way to stay in the loop and see what's going on.
I personally don't even like facebook that much and I never post things, but if I didn't have it at uni I don't think my experience would have been as good. Definitely get it.