Pros
Compensation packages are exceptional. Base salaries may not be on par with Google, but additional benefits add up fast. Bonuses are usually 10% and often better, up to 25% of base. Stock options (Restricted Stock Units, or RSUs) are awarded twice a year (the target varies, but so long as the company is doing well, the target is usually exceeded). The company offers a dollar-for-dollar match on 401k contributions worth up to 6% of your base salary, which is outrageously high for the private sector. And on top of that, P66 has the white rhino of private sector benefits: a pension, and it vests after just 3 years at the company. Additionally, that pension plan includes more stock options, called "Success Shares" that are dropped into your retirement account based on the overall performance of the business. Altogether, these financial benefits can easily be valued at 50% of your base salary, and the longer you stay, the better it gets. With the exception of refineries in New Jersey and California, most offices and facilities are in relatively low-tax, low-cost-of-living locations (especially HQ in Texas, a state with no personal income tax). Since the company is situated in the "midstream" (pipelines) and "downstream" (refineries, retail) segments of the energy industry, its stock price isn't heavily dependent on the price of oil; it's a company that takes oil & gas in, and then sends it back out as a new product, taking a relatively consistent margin all the time. This protects the firm's value - and therefore the value of your RSUs - against most market volatility. Yes, the company loves to talk up its employee-centric culture. But they back that up by comping people fairly well. It's the kind of chatter that I've heard before at other places, but it always sounded hollow when your sole benefit was something like a 2% match on 401k.
Cons
Limited vacation time (usually 10 days), but the company does have 10 dedicated holidays (Christmas, etc). Also, some jobs are eligible for the "19/30" program, which gives you an extra day off each moth so long as you work 8.5 hours per day (instead of 8 - up to you if you'd want to do that in any given month).