Pros
The people are smart, hard working, hard playing and care about one another. This isn't an office where you just know your peers while within the 9-5 — there is a genuine appreciation for knowing people on a personal level and supporting their various interests outside of the company. Cross departmental participation is very high. Lots of good perks and very comfortable offices. Nothing original there, but nice to know they have it. Waterfall has been around a while, so the office is filled with knowledge and a great mixture of senior and junior people. They also do a great job of recognizing contributions and strengths, and is not unusual for a person to start in one position but move to another that showcases those strengths and career ambitions a bit more completely. There is a real sense that greatness lies just around the corner, and that is contagious (and hard to find sometimes). Isn't this why were here in the first place? Technology is ridiculously forward thinking, sometimes possibly too much for its own good? Hah.
Cons
You're expected to contribute above and beyond what my experience in other companies has been. This isn't a bad thing, in my opinion, because the boundaries between work and real life are purposefully obliterated — coming in to work doesn't feel like a chore.