Avantages
Generally good access to facilities and helpful collaborators. Benefits were quite good.
Inconvénients
The group you are in matters. The larger group I was in was underresourced, and as a result had infighting between PIs, competition among students and postdocs, and a clique that actively sabotaged other group members. Other groups that I worked with did not have this problem. Career opportunities at the lab are rare, and in many cases promises of positions opening were made to me and others that never materialized. Only really a good place to be if your goal is an academic position. Postdoc salaries are not competitive with other national labs or positions in the Bay Area. Office of Science is getting squeezed by the current administration.