Avantages
A relatively generous benefits package that includes company matched contributions plus an semiannual contributions of company stock (alot) that you can immediately transfer to any other fund vanguard has. An annual bonus that usually averages around 8% (also depends on company performance) of your gross annual salary, you get your own office, state-of-the-art gym and soccer field with various exercise classes available for free to employees and family, flexible schedule, tuition reimbursement (90%), good work life balance (at least for software guys)
Inconvénients
Groups vary widely from each other and can have managers that are real slave drivers. Luckily, I'm not in one of those groups, but I have heard that for some groups Saturday is just another work day. ConocoPhillips likes to stick with older software platforms and has yet to take the leap to current technologies like GPGPU or even web services. It appears that software we end up supporting/developing has more to do with the person who yells the loudest, rather than what is truly useful or innovative. But, as long as you swim with the current, you'll be fine. Also, the career path for software developers isn't clear at ConocoPhillips, but who cares when you get a sweet benefits package.