Pros
I'm coming up to the end of my first quarter and continue to be blown away by how fast we can move, even compared to tiny startups. The engineering culture is aligned to enabling you to try things out, get things done and get them shipped out at an amazing rate. The perks are amazing and the management structure feels flat and low friction. Lots of smart folks and plenty of opportunities to get stuck into different areas if you feel like a change. Work/life balance is good; lots of encouragement to take a break when you need it with a pretty high frequency of offsite events, and flexible working hours. The onboarding process is very well put together: culture infusion from the moment you walk in the door, and you're mentored through a six week bootcamp and can be pushing code out to the website in your first week.
Cons
The flip side of the low friction management structure is that you need to take on more ownership of finding high impact work--don't expect to handed out work, you need to identify the work and then get it done. I see this as a plus, but it can make it a little difficult when you start out. Having a high density of smart folks can make it feel more competitive than it really is, and that combined with the pretty low average age of employees can result in the occasional abrasive conversation. Being privy to the roadmap and our plans overall but not being able to tell people about it when they interpret our steps towards our grand vision in a negative light can be frustrating.