Pros
OpenDNS is a stable, profitable company that provides a valuable and necessary service to the internet community. Working here makes you feel like what you're doing has a positive impact on the world because you're dealing with a fundamental aspect of what makes the internet work, and you're also working for a business that has very strong ethics such that they won't use their product to enable state censorship or repression. The people who work here are all great to work with, and the company happy hours and free lunches are a nice touch. This is far and away the best work environment I've been a part of.
Cons
No workplace is perfect, and while this one is no exception the cons are few and minor. You're given the space here to solve problems that arise and management makes it clear that their doors are always open, something I have personally found to be the case. In short, if you have a problem here then you're probably not being very assertive in addressing it.