Thanks Deeno & Mike - much appreciated.
Mike - Hard to describe these cameras if you're not particularly familiar with rangefinders vs SLR's.
1) For a modern-ish (2006) CCD (Kodak 10mp KAF) digital, the M8 is a low-tech, but very high quality rangefinder. It depends on its great lenses and internal mechanics - and you knowing how to expose a photograph. It does have aperture priority metering, but generally nothing else. I use it in manual mode anyway, setting both aperture and shutter values according to my external light meter and then focusing manually as well. Absolutely no automation, no autofocus - no fancy feature-fest of things everyone "has" to have in a digital camera. Simple, pure, fantastic.
File format is Adobe DNG (lossless RAW). It's also so much easier to carry for a whole day - a pleasure.
2) The M4-P is a 1983 35mm film model. It is completely and utterly manual in every sense of the word. No batteries included, as it were. It doesn't even have a shutter timer. What is does have are utterly smooth mechanics and a rubberised silk shutter curtain that is almost silent. It's solid as a brick and is deceptively heavy. This thing is my favourite. It'm going back to proper black and white film with this one - and developing it at home for subsequent scanning. I love this thing, and it's in fabulous condition. Made in Canada by Leitz, it brought Leica back from almost certain death back in the mid-80's and is considered by many to be one of the best - certainly by those who want the camera and nothing but a camera. A joy to use.