Pros
Interesting passionate colleagues who are extremely knowledgeable and willing to share. Office building prides itself on being green. Work-life balance is pretty good - most people have flexible hours or try to leave by a reasonable hour, though there are always workaholics.
Cons
Lower tiers (at least) are underpaid, relative to the value that they add to the work of the firm. The departments aren't really that well integrated, so often managers and higher ups are doing their own thing. Most of the work is grant-funded, so tends to stop when grants are done, and a lot of time is spent coding time billed to various projects. Can be a bit heavy on the bureaucracy at times in terms of publications, approvals, hr, etc. Advancement is usually dependent on attrition, so you may be waiting to move up the chain for a very long or very short time, and this isn't very dependent on meritocracy. They rely a lot on very cheap intern labor to fill lower tier slots, which otherwise would be full-time paid positions with benefits and a stable work flow.