Pros
Your learning opprotunity is HUGE! They send you to a Schlumberger school for 10 weeks (depending on what segment you're in) to learn all about your job. The learning curve is massive - you go from beign a trainee and not knowing ANYTING to running your own job in a matter of months. This is a great - out of college, get my hands dirty, extreme situation job. I would recommend it to other engineerings looking for a non-office type job. Also, this is an international company - so there is a VERY Good chance you will be working with someone from another country and/or going to another country to work.
Cons
As with other jobs - there are downsides. First of all - they dont tell you 100% of what you're getting yourself in to when you sign on. They try to do a good job of this - but every location is different. At some of the larger locations you can get lost in the crowd of engineers - my manager didnt know who I was for about 7 months. Also, some of the middle management isnt too professional but I think its a good learning experience on how to deal with difficult, unfriendly bosses. Also - they get really caught up in the fixed step training process that lasts from 3-5 years. In theory its a great thing, but they really look down upon leaving while still being in the program. Granted they do spend a lot of money on your training - you more than earn it back within your 1st few months of running jobs.