Years and years back I exchanged my Mamiya 64 for a Rolleiflex 3003 at a local shop.
It came with a manual listing a huge collection of accessories. Except for some remote controllers, backs and lenses I never found any of these in the real world...
WOW, if changing the film is timed down to the second then you need to go to digital!
I originally asked this question trying to find out a logical inexpensive way to try the RF world out! Even though I don't know much about RF's it doesn't take much knowledge to figure out that if seconds are that critical then maybe the older Leica bodies may not be the best choice for that shooting situation????
Back to my original question, where does the Zeiss Ikon fit in?
loading a modern leica takes only a little longer than any other 35mm manual camera. If it does the user is doing it wrong. The rigid back is a touch slower - a few seconds - but is no major issue. Its certainly secure, but thankfully I have never had to find out.
I do actually suggest a Leica if one can afford one without too much pain. They are lovely to use, very reliable and intuitive to use (IMO). I spent more on MPs because I felt it worthwhile and mine get used in the field. Just because it was worth it to me does not mean it will be to you of course.... I just felt I forgot about the camera better with a Leica than anythying else. I also get the distinct impression they suffer fewer RF alignment/drift issues than the ZI/Bessas - your mileage may vary of course.
As always, it all depends on what you do, where and how. And we all differ in these critical regards.
Keep in mind, we were talking about < $1000 Leicas. To my mind, that precludes the modern ones (M6, M7). If the user's budget is such that they are looking at a $400-700 M-mount Leica, that basically means an M2, M3, or a well used M4.