Ventajas
NI is a pretty great place to work. The people are smart and for the most part engaged in what they do. Management is relatively transparent and does a decent job of communicating company goals and results modulo the standard medium-to-big company stuff that everyone else does. New grads, it's worth remembering that NI is a pretty conservative engineering organization overall, so don't expect a downtown startup-like atmosphere or attitudes despite how young many of your fellow coworkers will be, but it's not totally sterile or button-down either.
Desventajas
Cheap. Compensation and benefits compare poorly to similar positions in Austin and don't seem to be keeping up even to the rising cost of living in the area, and Austin's not a cheap place to live anymore. Until recently, NI has argued fiscal austerity measures as the reason for the lack of salary increases and cutbacks in benefits; the relatively high attrition rate of experienced employees (especially the staff software engineers) and the competitive market for CS/EEs recently has kind of woken up management to the fact that they're going to have pay more to keep good people around. But this is a company that is thrifty to a fault, and expect penny pinching at every turn.