Pros
Dropbox is full of talented people with the freedom to express their talents. People have a lot of freedom to choose which projects they work on and how they work on them. And that culture extends throughout the company. The perks and benefits are good, and people use them. Free food is the norm in tech these days, but what Tuck Shop turns out is unlike anything I've seen at any other company. Actually, that doesn't do it justice. The Tuck Shop turns out food that can go toe-to-toe with any trendy SF restaurant you can name. Or you can always get a sandwich, a burger, pizza, or salad, if you're of the less adventurous type (but what's the fun in that?) There's also a slew of other benefits: health/vision/dental, 401k match, donation match, commuter benefit, cell phone, gym (both on-site w/ free laundry and a $100/month subsidy for an outside gym), basically, you name it, Dropbox has it. The culture embraces the fact that people work better when they have breaks, so people actually use their vacation days. And people work pretty flexible hours.
Cons
The pace of growth brings some problems. For one thing, everyone has to spend a lot of time interviewing potential new Dropboxers. For another, growth means every week there are more desks and fewer marginal spaces (e.g. couches) until we get more office space, and the people you're sitting next to today are unlikely to be the people you're sitting next to two months from now. Also, to make the freedom work, there are a lot of meetings.