I have a number of different camera brands and one of them, is a Leica rangefinder.
I bought mine in 1982. It is a llf (screw mount) with a Leitz Elmar collapsible, 50 mm F 3.5. The camera is of 1951 manufacture, the lens, well before that. Perhaps made in the '30's or '40's.
I've used it an awful lot in the more than 40 years I've had it. The leatherette is peeling off the body, there is a dent in the top, it's not pristine. The lens cap is off an old binocular of uncertain make and vintage.
I use my hand held light meters, all Sekonic, either my '60's L 86, or my more current L 398 Classic.
Focusing this old camera/lens even in very dim light is wonderfully easy...easier than any other manual focus system I've used. The pix are great. Very clear, great colour rendition...and there is something I can't describe in the pix....something extra. I can't explain it, but it is a certain Leica RF 'look'. I know it probably doesn't make any sense, but there it is.
I've run a lot of film through this old workhorse, over the decades...and given that it cost me about $ 330 CAD, back in '81, has required no repairs since I've had it...well that seems like a bargain to me.
Would I like a new Leica M11, with the Leica 35mm f/1.4 SUMMILUX-M lens. Sure, but at a little under 20 grand CAD, not likely unless I win the lottery.
Ergonomics...my old Elmar lens moves so smoothly, the focus engages so well...it is a pleasure to use it, every time I take it out.
I know my llf is sort of a Leica RF decontented model, no slower speeds, screw mount (I originally wanted an M3, couldn't afford it)....but all the Leica basics are there.
I'm a bit of a hot rodder...and back in the muscle car days of the '60's...we used to call, plain jane, stripper (little in the way of options) except for a big engine, and a manually shifter transmission (4 speed)....a sleeper.
My Leica llf and Leitz collapsible combo , I would say is a 'sleeper'. Nothing special to look at, a basic model...but even so, it makes surprising, crisp, sharp images....and it is lovely to feel how well all the controls work, given that the body has been around for over 70 years and the lens, longer than that.
I guess it has all the essential necessaries, nothing more, nothing less.
Somewhere in this long winded, personal assessment of my llf/Elmar....is my rationale of why this old, beat up rangefinder, works so darn well.
Well, that is my take on the Leica camera/ lenses....after 40 plus years of photography with this tough, little camera.