Merck has become a disgusting place to work. I'm in Operations, and deal with union employees regularly. This is like working with a large group of toddlers that you're trying to get to accomplish a task, except the toddlers have legal backing and higher salaries than you, so their temper tantrums usually mean more. In addition, being a manager at Merck means absolutely nothing, which is definitely not the norm - usually, going somewhere and being a manager has a certain power and responsibility with it, but at Merck it just means you're expected to work 16 hours/day, and whatever weekend you're needed, and be grateful.
The benefits have been decreasing A LOT since I started - health insurance quality has dropped, and has become more expensive. Also, educational assistance has become virtually nonexistent - the company will pay for the equivalent of 5 credits per year, making any degree not worth the time it would take.