Ventajas
The pay is OK, but negotiate your starting pay well, because you're likely stuck there. Good benefits and vacation if you're starting in the right place/level. Ability to work at home is great - limits commute, etc.
Desventajas
Managers abuse trust and loyalty and won't hesitate to backstab you if it advances their career, or saves their own skin. There will be no training, no information; just deadlines, panic and stress. The work moves fast and objectives are slippery - the goal posts are in constant motion. "Great year!" is what you'll hear 11 and a half months of the year, until review time, when the hammer drops and you move from a 5 to a 2 and no compensation increase. Your boss is going to get a fat bonus but say there's none for you (pay attention when you go interview - don't believe the bonus BS in the interview process; believe the luxury cars in management row and rust buckets in the rest of the lot).