Pros
Mozilla's mission (keeping the Web open, supporting literacy efforts, open innovation, net neutrality) is truly important and I believe Mozilla is in a unique position to drive progress in these areas. Chris Beard is a long time employee and contributor - he embodies the values of the mission. Great benefits, bonuses, gatherings in cool places twice per year. There are still some great people left who really care about the work we're supposed to be doing. There's some cool innovation going on (but we're not loud enough about it).
Cons
Politics have taken over and it's lead to a max exodus of people who truly care about Mozilla's mission and products. A new layer of management has come in and it is clear that many of them see Mozilla only as a means to another, higher position elsewhere. People are distrustful of one another and rightly so. In my department, we've started a massive process change and there's uncertainty about priorities and process on a day to day basis. This is causing uneasiness and backstabbing. Our department leads have acknowledged there's no clear career path forward using these new processes at this time.