Pros
Excellent teams across all functions - Engineering, Design, GTM. Humble and accessible founders. Product has found solid traction as a BI tool for the modern data stack with a clear set of capabilities to add to win more of the market. So execution oriented folks can stay focussed on getting a lot done.
Cons
At early and mid-stages of one's career, actually not too many cons. At the exec Product level, I struggled with clarity on who is accountable for what and the degree of alignment between the leadership on core questions relating to the product and company's purpose and identity. For anyone other than a handful of people in the leadership team, this is not a material concern. So I'd not think too much about it, unless you are interviewing for a role in the leadership team. If you are such a candidate, just spend a lot of time (as you should with any employer) talking to the founders, CEO and others in the CEO's team. I don't think any one individual's opinions (mine in this case) can be blindly applied to a general case - Sigma is, in general, a great place with well intentioned people. Fit is a personal equation, that's best evaluated by the individual.