Pros
The engineering team has a lot of really smart people with a variety of perspectives. This helps the team innovate rapidly and make progress towards meeting the business goals. The team is a good mix of keen people straight out of college all the way through to people who have been doing security for years and have done multiple successful startups. The company is well funded, and the track record of the CEO makes me confident that the company will be successful and hence financially rewarding for me.
Cons
A bunch of smart opinionated people don't always agree on everything (hah!). There can be some arguments -- especially between the more experienced members. The office location has its problems -- the traffic is already bad in the evening and developers are building another thousand (??) apartments on the street. It is going to become a nightmare.