Pros
Good pay ,lots of opportunity , you can choose your career pathway as you like . very diverse environment with smart people. very challenging job ( I worked as wireline field engineer ) with really good reward. Good opportunity to work in different location . Clear organisation and rules for promotion , very good internal control over the bias from standard or policy.
Cons
life and work were not balanced, you need to deal with that. Get ready to go home anytime , they don't care what have you done in the past, they have thousand of reasons get rid off you immediately unless you had good connection with upper management. Being in right place,right time with right people is the key for your success in this company , no matter how brilliant you are.