When I was shooting a lot of medical and scientific subjects, flat artwork, and architectural subjects with small format cameras, I often needed the 100% viewfinder accuracy for proper framing. The Nikon F, F2, F3, and F4 provided me with this very useful feature.

However, now that I shoot more vacation/travel subjects, I really prefer cameras (like rangefinders) that have more than 100% viewfinder coverage.

http://www.flickr.com/photos/11336821@N00/5219143020/