Pros
Overall I believe that an employee's overall experience at Y12 greatly depends on which department you wind up in. Some departments seem to have much more flexibility over the others in the work they do, not to mention that some are utterly boring. The work that is done at Y12 is cutting edge in the nuclear field even though a lot of the complex is outdated, which adds to the employee moral of 'being proud of the work you do.' Good pay. The name carries a lot of weight on resumes' if you decide to leave.
Cons
Obviously, a ton of red tape. It sometimes is to the point where you begin to question rather or not normal conversation is acceptable. The facility is outdated in most buildings so unless you wind up in a new one, have fun. Most employees seem to be content, with very few people pushing the limits of science and what is possible.