I use a lot of cameras without meters and I use the sunny 16 rule frequently, although I usually find it to be more like sunny 11 or sunny 13. It has to be pretty bright to go all the way to f16.

I even find it extremely handy when I am using a camera with a meter. I commonly look at the scene and the light, decide what I want my exposure settings to be, and then check the metering in the viewfinder to see if the camera agrees with me. I frequently go with my own settings even if the camera doesn't totally agree and I am rarely wrong on my exposures. My compositions are frequently screwed up, but the exposure usually comes out pretty good.