Pros
The people are great. The whole is greater than the sum of its parts, but the parts are pretty great to begin with. Humility is valued, and everyone in the company, from management to individual contributors seem to realize that the best idea can come from anywhere. I've never had an idea of mine dismissed because I don't come from a particular discipline, or area of expertise. I really love working with so many smart people. Big egos are not the norm, and usually don't stay here. It's also really encouraging to work with so many people who are willing to go above and beyond for the clients and for their team.
There's an honor-system policy for taking time off to attend to life's unexpected curve balls - awesome because nobody likes to take vacation time to be sick, or take care of a leaky roof, etc. The condensed summer hours (people can work 4 9's and take half-days on Fridays, or take every other Friday off) are pretty great as well. Basically, when it comes to getting things done, if you act like an adult, you're treated like an adult, and everyone gets their job done.
The training that's offered is pretty great too. Everyone takes a course in effective communication and emotional intelligence, based on the Meyers-Briggs personality test. I've found it really helpful in relating to coworkers because there's a baseline understanding of each other's personality. The company also recently paid for Scrum Product Owner training as well.
Then there's the regular perks - Bagel Mondays, catered lunches, Beer/Margarita Fridays, free books 3 times a year, and a selection of healthy drinks and snacks in the onsite pub.
Cons
Vacation time is really meager in your first year, but at least your accrual increases every year you've worked there.
Pay can be on the low end of the market for some positions.