Pros
There are a lot of really great people that work at SparkFun. What the company does is really cool. The building itself is quirky and fun, and the employee discount is great for parts.
Kontras
Literally no leadership. CEO has no idea how to be a CEO and gets lost in the weeds. He doesn't provide direction for the company and the result is a business that doesn't know what it wants to be. This causes stress for employees and results in some really weird business decisions. Environment can be a lot like high school, with cliques and gossip and backstabbing. There's very little professional respect for anyone who's not an engineer or developer. Culture is cult-like and misogynistic. If you're a woman and/or in a non-engineering field, this place is very frustrating and draining.