Pros
Decent pay, good benefits. You can make a surprising amount of money in a field known for terrible pay, especially after a couple years. If you are interested in opportunities in law enforcement later on, you may patiently get your feet wet here. Many have gone on to better things - police jobs, military, EMS, fire departments, employment within the hospital elsewhere, etc. If you are in school or balancing a second job, there is flexibility across the shifts and generally managers will help you to make it work. There is good money to be made via OT, details, etc. There are times, particularly when starting out, that the job can be fun and working alongside a good shift can be enjoyable. Also, if you prove you can do the job, they will take you back if you leave and need to come back.
Cons
The department is not a full fledged police agency, and management is steering more towards "security" then "policing". This leads to mixed expectations on all sides. Of you are a sworn officer with police powers, expect to be in sticky situations without any guidance. Arrests are frowned upon but letting someone slip by can also result in a write-up. Discretion is key. It gets old fast, too. You will deal with the same range of issues and perform the same tasks daily but there is little room for advancement as the organization is somewhat flat. Many officers get frustrated with the customer service oriented approach and the lack of management support when things do go wrong. Using force is sadly sometimes necessary but always ends up being controversial. Access control and other more mundane tasks take up a lot of time. It's part of the job, but a smarter plan for securing doors/lobbies during off hours would minimize this. It's possible to have a career here if management likes you and if you can last for the requisite ten years that will leave you as an un-fireable department fixture, but the lifers are bitter, unmotivated and often drag down the younger officers. Also, the main campus officers are held to a far higher standard then those at MGH satellite locations. It's insulting that they get paid the same.