Incredibly efficient, interesting and open. I had to decline the offer due to necessity - I'm relocating to a new country where Obsidian doesn't have a presence, so getting a valid visa was a priority - but even so it was painful for me to reject it. The tech stack is second to none and the projects seem extremely interesting. The people I spoke to were kind, smart and friendly. If you're passionate about functional programming, I believe this is one of the best places to apply to - strong recommend from me.