Works great as a reality check for your meter. Also, it is based on the latitude of Rochester, NY. Set shutter speed of 250 with Tri-X and develop per box time. Using the technique and preseting the F-stop frees the mind to see the decisive moment.
Even Adams could do it. :P
See the description of making "Moonrise over Hernandez"
I have always found that Sunny 16 is accurate, although in the upper latitudes it is more like Sunny 11.
It's a great guideline.
I like it more because it forces me to be cognizant of ambient lighting and changes, thus making me more involved in the photography. I enjoy the process of making a photo, perhaps more than the end result (which is often bad, lol). I like anything that helps me become more involved in that process (IE manual, analogue, mechanical cameras).
Unmentionable camera.....? Hahahaha... Is this serious? I thought Canon and Nikon would have this silly rivalry. Here, I said it. I have a Canon 30D as a backup body. My main body is a Canon 1d markIII with over $5k of lenses. I shoot paid gigs with my DSLR. In other times, I shoot with my medium format film body. Yashica Mat and soon to have Mamiya C330f.