Salaries are way below average and the growth rate of salaries is also extremely low. It is strange that NI is okay with senior-level engineers departing regularly instead of keeping them in house and rewarding them appropriately. This churn is especially evident at the 5-year mark, where the first round of RSUs (awarded with the job offer) are completely vested.
The low salary is fine if NI excelled in the other things--work/life balance, work hour flexibility, etc. However, this will completely depend on your manager. My new manager is not very open to work hour flexibility and as a result it doesn't make sense to be paid the amount you are and do the work you're expected to in a rigid work hour situation.
Even the industry itself is not very interesting for CS graduates since the majority of clients are other engineers. The technology that NI works on is very cool for Electrical and Mechanical Engineers because that is their calling. As a software engineer with only a CS background, you're a glorified code monkey. This is not NI's fault, but it is also a reason they don't retain a lot of CS talent. They are a hardware company at the forefront, and that is fairly obvious.
The short-term planning by the executives also leaves a lot to be desired. Management has flip-flopped between aggressively growing the company to staying even via attrition year-to-year. It seems they are not being as conservative as they were before in watching what the economy does (or modeling and predicting it accurately). What this means is that you end up with a lot of new hires during a recession with tenured employees having to be told that they'll be getting no bonuses and no raises.