Pros
Some of the brightest minds in the industry, if they are still there by the time you join. Pay is great for an entry level job, and you will be pushed to learn a lot, and very quickly. A year or two at DNAnexus will be an excellent investment in an early stage of your career. Excellent learning opportunity, join this startup to see what happens when doers' teamwork makes a company successful and "superstars" are brought in to "scale up".
Cons
Unpaid overtime is the rule. You will work on weekends, in the evenings, during your holidays. If you code; if you don't, you could probably work 9 hours a week and no one would blink. Toxic politics, teamwork for management is a zero sum game. Managers will actively sabotage career opportunities for their employees, as they feel constantly threatened by their own inadequacy. Most senior management has no basic understanding of the Genomics industry, so the entire business strategy is based on abandoning everything that made DNAnexus successful, desperately chasing other companies who actually know what they are doing. With 90% of the executive team doing sales and little else, the best exit strategy for DNAnexus is sharing the spoils.