I have a M3 - get one, it is a joy to use! Loading of the film is much faster and better in M3. Probably when you get used to it - screw mount loading is not painful also, but for me it was. M cameras are faster and better for shooting. Screw mount cameras are smaller and more pocketable - but not IIIg - it is big almost as M3.
@taysirco - yes rangefinder is 1.5x but viewfinder is 0.7.