Thanks for bringing this up; it's going to save me a lot of time: So I reckon I'll just repost from the above linked thread (context might see a little off, as in, "hey, no one has said anything about this in this current thread". But someone will, so...).
Before the cut & pasting, just want to stress that tunin's post regarding cost is something to truly consider. From what I understand, the technology for cramming a full frame sensor in a rangefinder is a bit more complicated, especially when addressing wide angle lens issues.
Also, on a broader level, technical perfection is not what photography is about, not even close; there are so many other factors.
While I'm at it, let me post this link again: http://lavidaleica.com/content/why-buy-leica
As I note below, given the gooey & sticky lovefest that L lenses stimulate on this site, let's be careful about deriding Leica because of "fanboism" or it's luxurious appeal.
Finally, keep in mind, rangefinders are not SLRs, and vice versa. There is, as noted in an earlier post, an apples & oranges aspect that often gets overlooked by people questioning Leica's appeal. If you see no use for rangefinders, great, but others do.
June 5:
"So who do you think is going to draw more attention while walking around in public; a guy dangling a Canon 1Ds series with a big white lens, or a guy with a Leica and 35mm lens?
Snob appeal? With Leica, you bet, but also with Nikon's and Canon's high end options, which, by the way, are far more conducive to showing off than a Leica, a brand name that largely only matters to other photographers.
Big honkin' white lens have far more superficial appeal in regards to the general public, and given all of the L deification on this site, let's not get carried away about what is jewelry and what is utilitarian. The number of people who buy DSLRs just to show off is far greater than the number of people who buy Leicas for whatever reason.
I've seen people get endlessly berated on this site for questioning the high cost of L lenses, but when people bring up Zeiss or Leica, it's practically de rigueur on this site to piss on these brands as being just overpriced lavish items.
For all I care, one can get superb shots from an iPhone (not being sarcastic!!!), but for f**k's sake, Leica is the only company right now that produces a full frame digital rangefinder, a professional 35mm camera that cost about the same as Nikon's and Canon's top offerings. If only one company produced a full frame DSLR, how much do you think it would cost?
Gripes about the Leica's sensor, LCD screen, and ISO issues, fine, but taking jabs at a rangefinder for not having autofocus and all the other gunk is pathetically missing the point…outright embarrassing.
Moreover, the M9 is considerably more discreet than are its DSLR's full frame counterparts. And when doing street, it's not just maintaining a low profile (as no camera is invisible) that's important, but the reaction the camera elicits when pointed at someone. I feel a lot more comfortable pointing a smaller camera at someone than I do larger one…aftermath is as much of a consideration as is initial inconspicuousness (unless you are Bruce Gilden).
I use a 60-year-old Leica iiif, and while living in Tokyo, I'd occasionally stop by the local Yodobashi, where I could fondle a 5D; how comically gargantuan it felt. We are discussing two very different types of cameras that both serve their purposes very well for their intended users.
If Leicas seem gratuitously exorbitant, then don't buy one. Very simple. But at least there's another choice, which in the digital world, particularly in terms of full frame sensors, is extremely limited."
