Pros
Job Security, that's all there is.
Cons
There is a reason there are frequent bullying surveys. All the things they say you will get as a civil servant such as support, training etc.. you wont. No one helps you on board in what is a very complex business environment and you will be held responsible for won't you did not do even though no one told you anything about it. Pressure piled on pressure. Aggressive managers. Long hours lots of unrealistic and unfair pressure. You will be 1 of very very few civil servants working with and managed by contractors on far more than you many of whom do far less work than you and working with suppliers who treat their staff better than you are treated by the HO and who are also earning more than you! Endless communications about the culture and values that bare no resemblance to your every day reality.