Pros
The company honestly feels like family - I knew everybody's name and got on well with everybody. They work hard to maintain their cultural identity which shows in how employees feel. The work was always rather interesting, being in a niche field means there's always more to learn. Being employee owned helped everyone feel responsible and also means that everybody stays up to date in the company as a whole. I only left due to a dream job opportunity coming up, otherwise I'd have happily stayed for as long as they'd have me.
Cons
Project goals and aims can sometimes be vague and changing, which can be addressed with better planning and mapping. However, ths is a known issue and when I left there were plans in place to improve this. Beyond that, honestly nothing. Depending on your view the location could be considered one but IMO it definitely isn't.