Depends on where you are in your career
Pros
Ample parking, a lot of learning opportunities if you can figure out how to navigate, onsite cafeteria with good and affordable food, onsite gym with free work out classes, charity events, enthusiastic culture, friendly people... the list could go on about those perks. As for career perks, it's a great place to start out your career after college or explore other career paths. Also great for outside hires coming in at a high level. Employees will never have to worry about social injustices such as racism, misogyny, homophobia, or just general assholism. Everyone gets a voice and ideas are always welcomed. Collaborative environment where everyone is always trying to come up with new ideas.
Cons
There is no structure or standard processes for anything, resulting in a chaotic work environment. Sometimes there is a little too much collaboration, resulting in nothing happening and sometimes things not working. A lot of disorganization and unclear reporting structures. Turn over is very high. The culture is very cliquey and there is a very clear "in" group the will reap benefits. Compensation growth or upward mobility is very vague. Comp and success are measured by merit via anonymous forms. The company tends to take advantage of eager people by exploiting their drive and willingness to take on many roles, but not pay them for performing multiple job functions. The company tries to operate like a start up despite acquiring mature businesses that are not start ups. Employees never know what to expect, but not in the spontaneous, thrilling sense. More like the "is my job going to disappear or get given to someone else" sense. There is a lack of strategy and vision throughout the entire company, most things are winged.