Pros
Good benefits and nice offices.
Cons
As an employee you are simply an asset for the sales department to sell, and if you are picky about your next client or role you'll get thrown off the bus. Many employees are somewhat forced to work on assignments they don't prefer, with the promise they might get something more suitable in the future. Leadership speaks about exciting clients, but many are in public sector or other dull organizations that find it hard to hire good tech talent (for obvious reasons). Middle-management is awfully substandard (and rarely seen), as most of the money is spent on company marketing and the sales department.