Prós
NI is a solid place to start your career. There is a fantastic focus on nurturing and developing talent, as well as hiring/promoting from within. Employees are also given a lot of freedom to take on their own initiatives. This combination of free and open with quality mentorship makes NI a big company that feels very small.
Contras
Compensation is always an issue, but I think that people feel underpaid because they compare themselves to similar titled position at other companies. The difference is that NI gives you high level positions very early on in a career, while other employers might require more tenure and advanced degrees. I am a Product Manager, a title that some people don't receive for 5-7 years after graduating (and possibly needing an MBA as well). I earned that title in three years after graduating with and undergrad degree.