Vantaggi
Generally -- campus environment offers gym facilities (with a fee), interesting events (e.g. frequent lectures, seminars, performance and sporting events, etc.) and access to intelligent people. There's also ample opportunity to work with students, if that's your thing.
Svantaggi
I've worked part-time in several different departments and in different positions, during my undergraduate and graduate time at UCLA. The work culture and experience can vary widely between departments, or labs. It can be difficult to predict this in advance of starting the position, without personally knowing someone already in the department or lab. Overall, I haven't had any problems, and in fact had great experiences at all of my positions. However, among my peers, I seem to be an anomaly. For example, some had technically incompetent supervisors, managers or colleagues. Others worked for faculty that was very out-of-touch, or labs with very little guidance (relatively common) and career development opportunities. Still others worked in very cut-throat, deadline-driven (e.g. for grants, publications, etc.) competitive environments. So it depends.