Pros
The lab is doing some great cutting-edge science, with fascinating work in a variety of engineering and science disciplines. Their campus is nice and well maintained, and they have a reasonably good HR and upper management. Their safety policies received some criticism for going overboard, but I think were well designed and well implemented.
Cons
While I applaud their efforts to do as much as possible with the limited funds available from government-funded science, there was constant pressure to perform well with barely adequate support, utilities, tools, and equipment. And their work planning seemed wastefully short-sighted and reactionary (although they were probably doing the best they could with the resources available). Thus a culture of apathy and resignation was the norm, at least within the group I was in (I get the sense that other groups had a more engaged culture, but I didn't get a chance to talk much to folks in other groups). And while senior management seemed interested and motivated to improve the culture, middle management hadn't gotten the memo yet and actively discouraged feedback and suggestions and discussion.