Dura Ace was more or less equivalent, being Shimano's top of the line group. For 9 out of 10 cyclists, it's going have about the same peformance.

Dura Ace cost a bit less. It was not quite as rugged and reliable as NR. It was more susceptible to crash damage. The hubs were nice but not magic smooth like Campy. The brakes didn't have as good fine modulation. The cranks were more prone to creaking. The brake levers sometimes broke. The RD sometimes broke. These difference in practice were relatively small, but they were there. Also, replacement parts were not readily available.