Pros
In my view Circonus is the quintessential startup even though it's been around for many years. There is great room to explore and try new methodologies, which is not something I have had access to historically. If you want to test and learn, in a safe space, this company is for you. If you need an army of people to get work done on your behalf, look elsewhere. You will be given some latitude to apply your skills in a complex and highly technical space, but you will need to step up and execute. So, if you're looking for a think tank, this isn't it. If you want to work in a place with solid values (which to me means, that leadership is made up of people with sound mind and good intentions who will stand beside the team when the going gets tough) then give this place a try. Also, if you're an engineer, the team is super solid. The founder is still heavily involved in the day to day operations so it's a great way to learn from not only a strong team, but the folks who built the product from the ground up. Also, the supporting teams are very receptive to engaging with engineering to support general understanding of the tech.
Cons
It's a small company with a majority of its staff working remotely, if you aren't comfortable working in a quiet space (which most of the time is what the office is like) then you should probably work somewhere else.