Pros
The company has both the intensity and flexibility of a startup (PTO time/snacks/etc.) The team members are some of the smartest human beings I have ever been in a room with. Working there was a perfect mixture of business strategizing interlaced with hypothetical thought exercises like "Is it possible to run a net-zero energy cycling gym by having the bikes produce electricity" And then actually deducing all the math necessary to figure out the answer. If you want to work with a world-class team and learn more than you ever thought you would be in a position, choose this company.
Cons
The usual downsides to a startup, an emotional roller coaster of ups and downs and you will be so invested in the companies success you will probably work more than 40 hours a week by choice.