Pros
NI has a great culture, having very very good balance between work life and personal life. There is a flexible schedule for many things (there is not a hard time in out to work) and a flexible attire. Work life is very relaxed having multiple opportunities for socialization between groups leading to a lot of opportunity for growth and learning. There are lots of development opportunities both technical and personal. Depending on the group, management is focused on developing and finding strengths than trying to work on areas of opportunity. The 100 year plan drives many business decisions over short term financial ones like the policy of no firing during recessions, etc.
Cons
Fast growing and this makes some of the great culture to suffer. The compensation is average. Sometimes there can be a lot of stress in the work cycles. Although this does not happens every time when it happens it can be difficult to deal with.