My advice would be M2, but by far the most advantageous point about using a rangefinder are the frame finders in the viewfinder. These are a wonderful aid to composition, allowing you to see above, below and right to left of the subject. Also, unlike an SLR you do not lose sight of the subject at the moment you click the shutter. Less moving parts with no mirrors chucking up clouds of dust in front of the focal plane. If you make the switch, welcome to the simplistic world of rangefinders. Don't worry about a meter, as if you stick with one film/developer/enlarger, you will soon find you don't need one.