Those great benefits come at the cost of a great salary until you break into the manager class, if you ever do.
They're very stingy with merit increases and one year we didn't receive them at all (they gave us two extra company holidays as compensation).
Despite having generally great health benefits, the sick leave policy is very restrictive. In order to utilize it as it's designed, you have to request it in 5-day increments and those days have to be consecutive workdays with no weekends or holidays in between. So basically, you have to get sick only on the weekends, make it to your doctor before the work week starts or early Monday morning, and then convince him or her to recommend at least five days of bed rest even if you really only need a day or two (good luck with that). The majority of cases in which people need sick leave don't require five consecutive days, so you're all but forced to use your PTO unless you're two, wobbly, precarious steps away from Death's door.
A seemingly shatterproof glass ceiling, especially if you're on the darker end of the racial spectrum. They have no problem hiring minorities, but promoting them to high-ranking positions is another story entirely. Regardless of race, I've seen people who worked there for a decade or more be passed over for promotions and positions for barely legal Kens & Barbies fresh from some no-name college.
The internal applicant process is a complete farce. I applied for numerous internal positions for which I was highly qualified and never even received an offer for an interview with the exception of one I received a full three months after I'd already left the company (and roughly eight months after I originally applied for the position). The HR office responsible for hiring in Atlanta, GA is located in Hershey, PA and they are more unresponsive than decayed roadkill.
The company has been going through "transformation" for over 5 years now. What this means is random mass layoffs in an effort to stop the organization from "hemorrhaging millions of dollars of donor money," yet they hire VPs and department heads with $400k+ salaries like it's going out of style (oh, and a million+ dollar CEO...with no medical degree...). Entire sections of cubicles are basically ghost towns. It wasn't uncommon to come back from lunch or a mandatory company event and find your friends and coworkers missing, their desks cleared out. This caused a very pervasive sense of unease because you were never sure who was next or if you/your team were going to be the next victims of "transformation."