Pros
Mozilla is one of the friendliest and most caring cultures around. The work being done on Diversity and Inclusion is authentic, and comes from a place of truly believing in doing the right thing. I'm a woman, and have been at Mozilla since 2011. Here is what has been consistently true in all that time: Co Workers are engaged, passionate, authentic and willing to help. It's possible to have real impact on a product or project because the Open Source ethos Mozilla grew from encourages discussion, participation, and getting sh*t done. Benefits, work/life balance, flexible working arrangements, bonus and comp are second to none. There is nothing better than knowing you work for an organization that is not driven by profits, but has the ability to help keep the Web open and free. Positive growth as an organization, professionally or personally is respected and encouraged. I've seen our organization through 4 CEOS in 6 years and I am confident that our current CEO believes in Mozilla, not as a vehicle for his ego, or for his intellect, but for the power of what we can do in the world. He also deeply cares about humans, while still being an exceptional systems thinker. I believe in him. I didn't believe in any of the other 3.
Cons
It's often true that we have perfection paralysis. We all care so much, that we can be afraid to ship something that isn't perfect. Because free and open discussion is encouraged at Mozilla, if you make a mistake, people will tell you about it. That can be hard to handle. Getting stuff done can be hard. The politics that other posters have spoken of is directly related to feeling like they might not have talked to the right person to get what they need, and operationally lots of things are still challenging. We grew so fast, that a lot of our support systems couldn't scale, we are still reaping the effects of that. There is definitely work here to redefine our operations and connective tissue, so that people who are having an impact can go faster, not slower. We need to invest in training for our people, professional development and making sure that our organizational development starts with a highly diverse population, and I believe innovation will skyrocket. There is work to do here too.