Keith
The best camera is one that still works!
I'm curious as to where you might get your Zeiss (if you go that way) in Australia. I looked at prices here and they were horribly expensive compared to OS so I bought from Matsuiya Store realising that if I have a problem with the camera it will have to go back to Japan for a warranty claim. So far so good.
I had an M5 for a year or two and it was OK ... in no way is it the camera that the Ikon is and at thirty something years old I wouldn't expect it to be. Yes sure ... it has a high build quality but the finder and metering system are way behing the Zeiss IMO. The viewfinder of the Ikon has to be seen to be believed and while your choice probably won't be based on this one point it doesn't need to be because everything else about the camera is excellent also.
The M5 is an interesting camera ... the Ikon is a great camera!
I had an M5 for a year or two and it was OK ... in no way is it the camera that the Ikon is and at thirty something years old I wouldn't expect it to be. Yes sure ... it has a high build quality but the finder and metering system are way behing the Zeiss IMO. The viewfinder of the Ikon has to be seen to be believed and while your choice probably won't be based on this one point it doesn't need to be because everything else about the camera is excellent also.
The M5 is an interesting camera ... the Ikon is a great camera!