Pros
In the past year and a half that I have been at AppNexus, I have experienced more professional and personal growth than the combined experiences of my time at college (four years) and my first job out of school (nearly two years). Working at AppNexus is fast, extremely challenging, and invigorating. The company — and, by extension, the industry — is not for the faint of heart, particularly if you work within Sales, Services, or even Product. However, if you embrace change and see each challenge as an opportunity to demonstrate excellence, then you'll do fine here and even possibly experience great success. Additionally, I truly feel privileged to work with such a genuine, fun, intelligent group of people. I can think of very few days in which I haven’t laughed out loud with my coworkers or learned something new from them. The education and entertainment never seems to stop. I truly believe that few companies like AppNexus exist and that this will be one of the "greats" that our children read about in school one day.
Cons
Change happens constantly and is a symptom not so much of lack of strategy or poor leadership, but of the industry in which AppNexus sits. While leadership and product strategy is strong, there often seems to be a disconnect between the top down Product strategy (sourced from executive feedback) and the ground up market feedback sourced from go to market teams. As with all fast-growing companies, AppNexus is experiencing growing pains.