Pros
The mission of the company/product is great, and it's delightful to see how being a values-driven business does permeate all levels of Etsy culture. From the local snacks in the kitchenettes to the way meetings are carried, Etsy is a company that walks the walk when they talk about being driven by a mission of empowering small local creators. Related to this is a great work/life balance. Etsy's a pretty cushy job.
Cons
On the engineering/product side of things, there's a pervasive fear of change at an institutional level means that anything that would improve the codebase or engineering process is a hard to impossible sell. Major "not invented here" syndrome means that engineers spend a lot of their time dealing with problems that are completely abstracted away in other similar engineering organizations because everyone's building on top of overengineered in-house tooling.