Ventajas
Salary is OK, benefits are good. If you're one of the people that have been hired as a Full-Time employee, congratulations. They'll never be able to get rid of you.
Work life balance is also pretty good with chances to obtain well-paid overtime hours.
Desventajas
If you're on contract or a back-fill, time to start sucking up to management as this is the only way you'll get to keep your job. Even then, likely they'll make cuts regardless of how important your position is.
Management and executives will swap roles, keep their friends close and you'll never likely get a chance to move up if you've ever given an opinion or gone against management or have had an independent thought.
"Agency transformation" is a ruse put on by management. From top down they'll tout this, but middle level down to employees, everyone is incredibly stubborn. No one wants any change, and they're happy doing things just the way they used to.