I had a post that my *&^*&^*)(* Windows 10 Surface Pro ate! F*(&*(*((* windows!
Take two.
On reflection I think they'll all be remembered in some sort of conflated manner. People will see them as niche at the time, but lots of niche variation at the time. You can go rangefinder, or viewfinder-less, you can have high magnification or low magnification, screw mount or M mount or Contax / Nikon Mount. You can go plastic, metal, limited edition, regular edition, black, grey, blue, olive and that plasticky silver. They came with as great and as varied a range of wide-angled and normal lenses as has ever been offered by any maker. They were expensive enough, but not rolled in unobtanium dust by German pixies; so they appeared cheap and people (i.e. men mostly) could 'come into the fold' (after arguing value with significant others) and buy a new rangefinder.
I think these qualities will get conflated into a conceptual idea that will see all Bessa's remain memorable.
If I had to pick one though, I would go Bessa R. The L was first of course, but it feels more like a camera to sell a lens than a product like the R that people might have actually been looking for or become converted by - even if they didn't know they were looking for something like a new rangefinder. I think the R though was good enough that it would have appealed to those that already knew about rangefinders, but in a left of centre sort of way. However unlike the L, it wasn't so off the grid that it wouldn't also appeal to rangefinder neophytes. And it spawned a line of successor models.
I remember thinking back in 2003/4 as I ogled Bessa's on Stephen's site that a Bessa L was pretty cool, but a viewfinder-less camera body, for $79! How was that going to work? So perhaps the L is too niche to ever be truly memorable. But the R spawned a line of cameras and did so using existing manufacturing tech in an interesting and unexpected way to produce a rangefinder, as opposed to a light tight box. All whilst digital was sweeping the world.