Pros
The people you meet in the company are amazing humans. They are highly motivated, talented and accomplished people you wouldn't otherwise meet elsewhere. The job also allows you to meet people from all over the world. The team that I was in was the best. I loved my team and my boss. The company had also given a lot of flexibility with our working styles and work time that is not normal in Japan.
Cons
Unfortunately, some processes in the company can be quite archaic despite it's small size. The turnover rate is also extremely high because the work distribution is bad and work efficiency is low. The efficiency is not the fault of a single person but multiple factors. I had attempted to help with increasing the efficiency but ran into multiple issues, a large one being the mindset of the senior management and the consistent pressure to perform (bring in short term profits). Working also in a division where KPI was not easily measured, we faced a lot of difficulty in being understood as our wins were smaller and not seen as quickly.