Pros
Great work/life flexibility. If you need to schedule a doctor's appointment, run out to meet the bus or take a sick day, just do it and let your manager know. Generally no need for prior approval. You can make your own schedule (within reason) and as long as you perform, no one's watching to make sure you're at your desk or online at given hours. Great on-site services - cafes, health care, child care, fitness center and more. Beautiful campus with walking trails, softball and soccer fields, picnic shelter, artwork. Almost everyone gets a private office. Family atmosphere - low turnover means people form lifelong connections and friendships.
Cons
Mobility - low turnover also means it's tough to advance or even move laterally. Most people have been around 12+ years, so everyone is senior level and up.