Pros
Flexible hours and decent pay for a manageable amount of work are common for student worker positions all over the school. They never schedule you during Finals (with prior notice for some departments) and getting a day off is usually negotiable. Certain departments have student worker positions that can actually be useful in a resume (i.e. supervisor, manager, director, coordinator). Make sure to ask what opportunities are available. Given the nature of our situation (attending school full time), the benefits will outweigh the many cons (especially if you take 16-20 units a quarter like I do) - unless you can land a part time job in your career field, at that point, get the hell out. If you have a busy schedule outside of work, have several extracurriculars or devote your time to something that matters, a college job is the way to go.
Cons
Depending on where you work, office politics can affect even the pawns of UCLA, the student workers. The overall structure of the entire school is efficient in terms of getting the work done but you will notice there is a lot of wasted money all over. Upper management will NEVER listen to the suggestions of the individuals who are doing the actual work, often resulting in many employees lacking the tools and training necessary to complete their tasks. Student worker positions, in particular, see a lot turnover and lack of training is evident in many areas. Lastly, management greed often leads to treating student workers as full timers and are expected to bend over backwards in terms of availability during last-minute scheduling.