Pros
Able to work part time, enthusiastic colleagues, a supervisor with high level of integrity, and an opportunity to work with colleagues in other departments on interesting projects are all pros that I experienced. Beautiful views of the Bay didn't hurt either.
Cons
Hard to find funding, and during the slow times work can be boring. Work at my level came in waves. Also, part-time workers are discouraged against (a manager once told me that management likes to see people in their chairs or at their lab bench every day). Not to mention the fact that it takes forever to get funding and complete projects (too many internal hurdles related to management approving particulars of the research, as well as internal departments such as budget office etc). Oh yes, and VERY HIGH overhead, making it impossible to get adequate funding to fund a multi-year study with 3-4 people working more than 50% time on the study. A lot of my colleagues took "leave without pay" days just to finish a study. Seems that LBNL ultimately wants "star scientists" to lead multidisciplinary teams with groundwork carried out by Graduate Students. So, if you are somewhere in the middle, your work environment may not be that stellar and you may not have a chance to move upward. Lastly, some laboratory equipment outside the ALS and Physical Biosciences Division is very out of date, definately not "state of the art".