People didn't adapt rangefinders out of fondness for the rangefinder mechanism, IMHO -- they did it because it was the best way to focus, until SLRs came along. After that, some people stayed with rangefinders because they were relatively compact and they simply liked them better. Between the two types, there really wasn't much difference in image quality, because they used the same films.
But SLRs and then DSLRs got the bloat. There's really not much difference in frontal area between a Nikon D3/Canon 1Ds and a big fat Speed Graphic...and with lenses, the Speeds were probably lighter. (I'm writing this off the top of my head, so I'm not sure about those weights.)
At a time when the Speed Graphics ruled, photographers, and especially war photographers and then other journalists, went to "miniature cameras' i.e. 35mm, because they were light and handy. And, critically, the IQ was "good enough" for magazine and newspaper purposes.
It seems to me that the same thing is happening all over, in a somewhat more complicated scenario, because there are three contestants, rather than two.
Against rangefinders, M4/3 offers the small-size advantage, and also offer modern focusing and viewing systems, including autofocus and image stabilization, and the possibility of genuinely long lenses. The KEY in this competition is the modern features offered by m4/3.
DSLRs have better IQ than m4/3, just as a good 4x5 Speed had better image quality than an early 35...but, the DSLRs are big and fat and bloated, and not too much can be done about that. To some extent, body size and, importantly, lens size, is determined by sensor size. I have a Pentax K-5, which has a very small body for a DSLR. It dwarfs my GF1. The KEY to m4/3 versus DSLRs is size -- just as it was in 35mm vs. Speeds. I can carry my complete m4/3 system -- two bodies, several lenses, four batteries, chargers, etc., and Mac Air (and accessories) in a Pelican briefcase.
The m4/3 also offers image quality that is "good enough" for most purposes -- all purposes on the net, and good enough for most magazine and newspaper work.
Like most people here, I have a bunch of different cameras, including a Leica M7 and M8 and several lenses, which may be on the way out; a Nikon D3 and D300, which I may also be phasing out, depending on my experiments with the K-5; a Panasonic GF1 and GH1, my current go-to system; and the K-5. I generally want three camera systems, I think -- a pocket camera, like the Canon S95; a travel and street set, which is where the m4/3 cameras shine; and a heavy duty, APS-C or Nikon full-frame system.
But, if Panasonic comes up with a sensor that matches that in the K-5, I may stay with any new heavy system at all. The m4/3 will simply be good enough for me.
JC
