Vantaggi
Set hours (M-F, 8-5) didn't matter, when you worked was irrelevant and not monitored/tracked closely (for salaried), all we cared about was just getting it done, when we say we will get it done. There was a lot of trust built in, in that regard - it's likely there were some who took advantage of that, but for the most part employees respect and honor that, and let their performance and contributions speak for them. I loved my coworkers - they made the often late nights, early mornings, and weekends very enjoyable. Looking back, I can truly say that Merck hired the best and brightest. Top talent in the industry. Being as mature as it is, Merck has well-developed processes that are (for the most part) logical, clearly defined, and well-controlled.
Svantaggi
Pay did not match the hours, responsibilities, or, most importantly, contributions. "Rigid" pay scales, with huge ($40k) ranges, meant that someone who fulfilled the requirements of their job was getting paid the same amount, and if they had a couple more years experience, significantly more, than a younger colleague of the same level who consistently went above and beyond their duties and responsibilities. Advancement - stagnant for years on end. You will take on more responsilibities, which are phrased to you to make them sound like an honor or a privilege, but in reality management is slowly just transforming you into doing the work of 4 people for the price of 1. In the nearly 4 years I was there, I saw 3 reorganizations and had 3 different bosses, and saw numerous layoffs. Culture steadily become more high-stress, anxiety-driven, as a result.