I'm glad I got the bus pass as a fresher but I wouldn't again, the walks not bad and if you've got a bike it's fine, but it's good for meeting people and you don't want to be the only one in your flat not getting the bus.
If you're in Mary Gee and likely to have morning lectures don't bother, most of the buses don't stop because they're full.
Oh, and bus prices are really expensive if you don't have a bus pass.