Pros
Great equipment (for all employees): new laptops and peripherals, as many monitors as you need, standing desks, noise-cancelling headphones, software licenses. If all this isn't enough, management is open to ordering something that makes your day even more comfortable/efficient. Choose your OS: Linux, MacOS and Windows are all allowed here. Open culture: This place is politics-free. There is certainly a separation felt between BE/FE/SF/PM teams but at the end of the day it feels like being part of one big family. Face-to-face feedback and communication is encouraged. There are frequent outings, sponsored events and happy hours (which are completely optional - no one is judged for not hanging out outside of work). Our CEO doesn't have his own office and is always open to conversation. I was skeptical when I first started about the culture here - there is a lot that sounds too good to be true, but now I can't imagine leaving. Growth: Seemingly each week we hear about new clients coming to us for work, new project teams being formed and with that new internal practices that support growth.
Cons
It's possible you'll be on a project without a "lead" developer, leading to some bad practices and code bases that get out of control. I think this one of the side effects of having a flat structure. It can get loud, but that's the issue with any open office.