Ventajas
They are good people to work for and work with. There is mutual respect for each others professional point of view. Ethical and safe behavior is expected from all employees and is practiced at all levels of management. Input into decisions and work processes is encouraged and self-direction is expected. Although this is not true for most of Shell, Shell Pipeline in Houston still has private offices, which is a bonus. Shell Pipeline, like most of Shell in the US, is on the 9/80 (80 hours in 9 days) program where we work 9 hour days and get every other Friday off. Overtime is kept to a minimum. Also, bus fare (or parking) is subsidized.
Desventajas
The only downside I can think of is the commute to downtown Houston. Though I have done it for so long that I am used to it.