Pros
Princeton offers a beautiful campus, a generous stipend, and average healthcare benefits for its graduate students. The gym is free, although special fitness courses cost a per-class fee. Most PhDs offer you a masters degree after qualifying, which isn't true everywhere. It seems like they are trying to take steps to get their graduate students hired in the 'real world', given the terrible outlook for postdocs in academia. Not sure that the PIs understand this, however.
Cons
Princeton is an undergraduate-centered university. The department claims you will be able to choose your TA position -- not true, unless your PI is teaching a class and they specifically ask for you. Management depends on the PI you work for. Some are kind, some are abusive verbally / emotionally, but that isn't uncommon in this field. This behavior doesn't seem to be acknowledged by the department or "higher ups"... horrible PI's keep getting promoted. the student community is poor, enthusiasm is low, and departments don't do much to counteract this.