Pros
Wonderful culture (at least in my group, this can vary across Groups and divisions), brilliant, humble, and helpful people, amazing plethora of projects to work on, and fantastic work-life balance and respect of boundaries. Great pay and benefits for an FFRDC.
Cons
Some time expectations of what one should be doing as a technical staff aren't clear, there's so many ways to exist as one at the lab and so many potential paths one can take. However, this is pretty minor compared to the pros. Also, bonuses would be nice