The three best cameras on your list are the QL17, Yashica GSN, and the Olympus 35 RD.

The Canonet QL17 is nice because it has a mechanical shutter which can run without batteries, and it has a very good lens. The drawbacks are that the meter only works with the camera is in automatic mode. And, the automatic mode is shutter-priority, which isn't very intuitive.

The Yashica GSN arguably has a better lens than the Canonet. The GSN is also easier to use, and is an aperture-priority camera. It's main drawback is that it has an electronic shutter which is automatic only, and it is a rather large and heavy camera. Those things aside, the Yashica GSN is capable of taking superb photos.

The Olympus RD is a jewel compared to the QL17 or the GSN. It has a wonderful lens, and it also has a mechanical shutter. Unfortunately, it is not an easy camera to find, and it is not cheap.

A camera which is not on your list, but which is superior to them all is probably the Olympus 35 SP. The SP has an excellent lens, a mechanical shutter, and a spot meter function. The spot meter allows for far more accurate metering than you can get with any other rangefinder camera. I often leave my Leicas at home and grab my SP when I'm going to be shooting in conditions with lots of contrast (sun and shadows). It simply does the job better than anything else of it's type.

Other good cameras worth considering are the Yashica CC or GX, the Konica C35, or C35 FD, and the Olympus 35 RC.