Pros
The SUP community is very tight. I felt comfortable from day one. It's also the best place to network with interesting people/companies and to learn new things. The "horizontal structure" of the company was great. Even as the de facto lowest rung of the ladder, I was always treated with the utmost respect and allowed to pursue company and personal goals in the way that I thought best. I loved my coworkers; truly some of the best people I know. Interacting with them during the day to day made work delightful, and after work events were a blast. They were very accommodating regarding hours and very supportive of me personally. The company itself is doing very cool work and is a huge asset to the startup community in Stockholm.
Cons
There were some times when I felt a little more guidance on projects would have been helpful. There weren't many, because I'm good at self-motivating and working with vague instructions, but occasionally I was left wondering exactly the purpose or reason for a particular task. However, I can't stress enough how minor this was. It happened only a couple times, was quickly remedied, and never detracted from how great the job was.