Pros
Competitive pay, extremely easy work (though pointless or meaningless at times) flexible work arrangements, constant change for those who have occupational ADD, work/life balance is excellent, great offices in Herndon/Reston. If you can tolerate "pretend work" for grossly inflated compensation in comparison to what is expected, then Fannie Mae is the best place to work around. If you want to climb the corporate ladder and advance quickly, nuzzle up to a Senior Executive and do everything you are told, otherwise use your brains and look for truly meaningful work elsewhere.
Cons
Poor communication, hard to keep up with constant change, several groups/people duplicating effort or going a different direction, shoot-from-the-hip "strategic" planning, work efforts seem impulsive without attention to long term goals, worthless/repetitive meetings without agendas/action items, lots of meetings but nothing is actually accomplished, group think and acquiring consensus/approval is extreme, mindless projects = "progress," project efforts are critical one week then non-existent the next, smart managers but who are very quickly seduced by the corporate kool-aid, no one seems to really know where we are going or how we are going to get there, gossip, passive aggressive co-workers who are easily threatened, aversion to new ideas with certain processes ("this is how we do it here"), intense dislike for contractors, constant flux of insourcing then outsourcing and vice versa, too much broad/vague corporate motivational/principles crap. FNMA tries waaaay too hard to label itself a world class company when it is really a chaotic mess with an average workforce at best.