Pros
GitHub is a great place to come and explore what it looks means to be apart of something special. There are a ton of great people here who are passionate about what they do. GitHub is more than generous with pay, benefits, flexibility, work/life balance, and they really do care about employee happiness and well being. They have a social impact team that is basically dedicated to saving the world -- which is amazing.
Cons
There are a few bad apples that make the experience less than ideal -- but that's been the case at nearly every company I've been to. If you're not in engineering or the technical side of the house, you're nearly a second class citizen. Engineering doesn't have enough structure, code base is a little outdated on some projects, and their is no clear product vision. Nevertheless, when engineering does put out a new feature or product it's actually an A+ ship. Sales is a catch 22. Really strong team members, not enough good managers. Marketing is in the same position as sales. Most roles don't have a 2-5 year plan -- meaning, there is no clear path for career growth.