Pros
There are some great people here and exiting projects.
Cons
Plagued with mismanagement and a deeply rooted "cronyism" culture, today's Fermilab reached a new low point in employee satisfaction and governmental inefficiency. It became a machine that grinds through post-docs and spit them out to the street to survive. Fermilab doesn't offer any career path for their post-docs unless you are in the know and one of the cronies of someone higher up. Without question, every entry level scientist/physicist position has "a candidate in mind" and other candidates are only interviewed to maintain the facade and meet legal hiring requirements. In layman terms, unless you know someone, how hard you worked or your accomplishments will not matter at the end of the day for any hiring decision. This is also infuriating because most of the employees do barely any work, projects are carried by few dedicated people. All of this is mostly true for other labs too, this means in practice they also tend to hire their own cronies so if you couldn't get a position in your own coop, you have little chance elsewhere. But don't take my word for it, please search for "Fermilab whistleblower report arxiv" and draw your own conclusions. My advice to you, dear science-loving newly appointed post-doc fellow, is the following; If you do not get a permanent position within three years, just move on and don't lose time here. Instead work on something that could get you your next job.