Avantages
Good benefits, low stress, low accountability. Good financial/retirement, medical, and workplace flexibility benefits. Low stress, due to nonprofit nature and self-defined deadlines. Low accountability, as many customers don't expect specific deliverables so much as giving a good effort to solve their problems.
Inconvénients
Good benefits, low stress, low accountability. Good benefits lead to entitlement and abuse of benefits such as unlimited sick time, family medical/leave time, flexible hours, and working from home. Low stress leads to lack of motivation and sense of urgency. There is such a thing as "good stress", or at least a "good stretch". Low accountability, as when cost targets or deadlines are missed, the project plan just gets a replan month after month.