In another post, I also recommended getting a Kodak Medalist II and having it overhauled and converted to 120 film by Ken Ruth of Bald Mountain. It is a heavy, bulky beast, but with unbeatable image quality.
My Bessa RF is far lighter, and more fragile feeling. However, it folds up compactly. Thus the Bessa RF is usually the one going out with me.
With any of these cameras, tripods are highly recommended. Their shutter releases are not as smooth as that on your Leica M3. When trying to release the shutter, there is a very good chance of shaking the camera.