Vantaggi
You're furthering a mission that's actually worth something positive for the world. The technology can be very forward leaning, depending on the group you're working with. Nice office space and generally smart co-workers.
Svantaggi
The kind of work you'll get to do can be highly variable in terms of how interesting it is based on what team you're working with. Of the major IT groups, NYTD probably gets the most interesting work on a day to day basis. Be forewarned that some of the middle management are absolutely terrible and can be very demoralizing to work for if you're unlucky enough to land on their team, and the higher management is not clueful enough to notice (or, worse, doesn't care) that some teams have double-digit annual turnover while others in the same group have zero.