Pros
Please note: This review is specific to my experience at the McCormick School of Engineering. Jobs at Northwestern vary considerably because the school contains a huge number of entities, each with their own reporting structure. That said: Northwestern is a wonderful place to work. Beautiful campus, talented and smart people, and what seemed to be above-average compensation. I worked with one of the best teams I've ever worked with, led by probably the best manager I've ever worked for, and it was a pleasure. Benefits are very good overall as well. Ideal for someone who'll soon have a kid in college as well — they do a tuition exchange program that can knock thousands off your dependent child's bill, even if he or she doesn't go to Northwestern.
Cons
If you live in Chicago, depending on where you're located it can be kind of a long commute if you're using the CTA. Driving is actually a better way to get there if you're in north-central to north Chicago anywhere near Lake Shore. Also: For a time I was a half-time employee, and during this time the school charged me twice the rate for my health benefits that I would've been paying as a full-time employee. In other words: Half the pay, twice the health costs. This caused me a lot of problems financially.