Pros
Bright, talented, and motivated employees. You will learn a lot from the other people who work here if you make the effort to do so. It's generally easy to make things happen with little in the way of bureaucracy and to make your voice heard by your manager or your colleagues. Flexible working hours and what ultimately matters is getting the job done. Unlimited paid time off is nice in theory although I haven't made much use of it in practice. Free weekly massages are awesome. Abundant free food and beverages. Fun social events and many other efforts to integrate employees into company life.
Cons
Compensation is the biggest concern as it is below that of competitors in the industry and certainly below average in the broader technology sector. The culture and working environment is so positive that the consequences on employee attrition have been pretty minimal, but it has been and will continue to be an issue. Not all employees embody the collaborative spirit that we aspire to and can be difficult to work with or completely non-responsive. I know of at least one employee who is a poor performer and not well-regarded by peers who has worked here for a long time and received promotions purely through their personal relationships with senior management. For my functional role here, my learning curve has flattened considerably since earlier in my time here and it's unclear what are my career development prospects if I stay with my current group.