The long and the short of reference managers is this: You need one.
Which one you should use depends largely on how you work and your comfort level with various types of software. I strongly suggest trying more than one before you settle on one. You are not limited to the one that is provided by your school (if any). Here is a Wikipedia comparison of reference managers that includes more than a dozen options.
That said, there are benefits of using the same reference manager as the other people in your labs or publication groups.