Pros
Product Team Structure - Engineering teams at Zillow have clearly defined goals and ownerships. I know what my team needs to do we can usually get it done without spending ages talking and coordinating with other teams.
Company Vision - Management does a good job of communicating where the company is going both in the next months and years and make it clear how everyone fits into that plan and how their work contributes to that goal.
Ownership - I don't know anyone at Zillow who feels their job isn't important, or as a joke goes is responsible for polishing the print button, everyone can get enough responsibility to push themselves to the limit.
Opportunities for growth - My manager sincerely cares about my success and helps identify ways for me to improve and grow. I feel that my career has accelerated since I've joined Zillow.
Company culture - I can tell that everyone I work with wants to be there and cares about their job and the success of the company. Working in a place like this is inspiring and pushes me to perform better.
Benefits & Pay - Zillow benefits and pay have become more competitive over the last few years. It's especially good if you're bullish on the stock, because bonuses are still paid in stock options. Also, as of today there's a discretionary time off policy which means you can take as much time off as you see fit.
Work/Life Balance - many people I know work 40-50 hours per week and are successful. There's no pressure to work overtime unless there's an exceptional business need.
Office - The office in downtown Seattle is amazing. Great views, standing desks, snacks, coffee & espresso machines, and weekly yoga.
Cons
Stock Options - depending on when you got your stock and when you plan to cash it in these can work against you compared to how you're paid at other big companies. I think this is a good con and filters for the right people.
Change/Growth - Zillow is growing quickly and so far has managed to deal with the larger size well, but this is always going to be a risk. It's no longer a start-up.