Pros
Excellent people, really good culture and work atmosphere. Laid back and casual, but hard workers who are all results oriented. They make an effort to keep employees happy with free bagel days, candy bowls, quarterly company events and department specific offsite activities. Very good with flexibility and work/life balance. This is a place where people are generally happy to stay for a few years.
Cons
There has been a lot of change in the past 2 years, you could call them growing pains, but the verdict is still out on if there plans will work. Changes included some members of the senior staff leaving or getting pushed out, the entire marketing department leaving one after another, and the ENTIRE senior staff getting replaced by people from Arena's former competitor. This has led to a little bit of culture shock and not everyone had been thrilled working for the new staff. Hopefully these relationships will continue to improve. There is a cafeteria in walking distance, but you need to drive to San Mateo to get anything decent.