Pros
Promega is kind of an old-school company, in the best sense. They hire people who are the best fit for the company, not just who may have the best credentials (but this is more important in R&D and product management roles). I've seen so many cases where someone really started at ground zero in terms of experience and rose up the ranks. It goes to show you that they do invest in their people, and that is why there's so many who have stuck around for decades. In my experience management is highly supportive of learning, innovation, and creativity, so if you have a good idea that shows promise you'll probably have the opportunity to explore it.
Cons
At times, there is such a strong focus on the newest thing, with the priorities changing very quickly. Due to this there are cases when there isn't enough time to develop a fully mature product, or gauge it's effectiveness. To be fair this is a problem in most organizations, but you can end up feeling a little disoriented by the rapidly shifting landscape. I would say this could be a challenging environment for someone who is slow to adapt or pick up new technical skills.