Pros
There are so many pros. But I am particularly impressed with how Zillow has created what most companies struggle most to achieve; humanity and humility at all levels of the company. The leadership culture of many, if not most, companies either originates with, or evolves over time into a self-protecting aristocracy. Leaders ride on the backs of, and take personal credit for the productive work of those they manage. They look out for 'threats' and protect their narrowly-defined turf. Ugh. It is so typical it is almost an office culture cliche. Not so Zillow. Zillow is a team sport. Throughout the C-suite, VPs and Directors there is an appreciation for 'collaboration' that goes well-beyond the lip service other companies pay to the concept. The CEO, CFO,CMO COO etc. do not have their own offices. They are readily available and view their respective roles as one part of an enterprise that is driven by the creativity of those they work with. This is a modern business, so there is a hierarchical reporting structure, but this traditional necessity is reluctantly superimposed on a culture ingrained with egalitarian meritocratic ideals. No matter what your official title, if you have an idea/concern/critique you express it...to whomever is in the room. Also, the founders, CEO and others in leadership positions clearly want to make Zillow as civil a work environment as they can while also encouraging a relentless drive for success (Core Value: Winning is Fun). It seems that their model for a successful company is realized through a supportive environment where individual risk taking does not equate to 'risking ones job' and proposing innovative ideas is not considered a way of 'sticking your neck out'. From my experience, tech companies that get all rigid with an unaccountable leadership class wither and die, or get blindsided by more agile, companies with non-hierarchical cultures...like Zillow. Zillow was conceived by civic minded, yet highly competitive innovators and savvy business people. The company culture is organized along these lines as well.
Cons
If you are seeking promotion through bluff, bluster, or office-scheming rather than through repeated demonstrations of your competence. Or if you manage-up well and manage-down poorly. Then this company really sucks.