Norton's has weaknesses which other reviewers have pointed out, to be sure, but a tremendous advantage is its layout of the star charts. Unlike most other charts out there, it shows huge swaths of the sky (60 degrees north to 60 degrees south, and well over 4 hours in RA) just as you see them when you're out in the dark trying to get oriented in Deep Heaven. Other charts show little chunks of sky--Norton's shows just what you see in a great wide band from well behind the zenith to further south than most of us will ever see.
And as someone else pointed out, the reference material interleaved between the sky charts, though not exhaustive, is very useful. I use Norton's constantly along with the Sky Atlas 2000 and Burnham's Celestial Handbook (and websites to update Burnham's data), and the combination of the three is perfect for most of my own observing. I have dozens of other books on my shelves but these are the ones I rely on.
For teaching astronomy I substitute the Audubon Field Guide to the Night Sky for the Sky Atlas and Burnham's, and my students love it because Norton's helps them find their way around the sky and the Field Guide description of the constellations tells them about what they see. If I were stranded on a desert island (hope, hope) and couldn't take my beloved and well-annotated Sky Atlas 2000 and Burnham's, I'd take Norton's and the Audubon Field Guide as a very good substitute. I always recommend Norton's, the Audubon Field Guide, and binoculars to beginners--the Sky Atlas 2000, Burnham's, and a telescope can come later (or sooner, for the passionate).