I think to have addressed all the questions.
Let's sum it up again: you can't compare a digital P&S to a digital rangefinder.
You can't compare (easily, need thousands of pages and philosophers too) film to digital.
You can't compare a modern digital DSLR to a rangefinder.
You can compare some results, taking into account only the sensor characteristics. Or to see what the same lens produces on film and on sensor, in the case of Leica (I'd say only with M9, to be precise).
Or you may have simplistic answers, some saying the D90 sensor is better, some saying the M series sensor is better. Cause there too there is a "philosophical" choice.
Want megapixels and low light capabilities? Want superior contrast and definition?
Want them compact or like best large? Care at the lens quality? Care at the value your stuff maintains over the years?
My opinion? every camera around has enough quality to print good and sellable images. Except for the requirements by large online agencies, that are commercially and consumeristically driven.
"IQ comparison" is highly subjective, and I'm sure this forum is far from such pixel-peeping way of life.
Or, at best, you can have an answer like this:
X1 IQ is better than any other compact, M8 IQ is better than any modern DSLR except perhaps the first Kodak, M9 IQ is just superior.
M≤6 IQ is out of discussion.
It seems that everyone has been offended by the joke reference in the OP, and as a consequence few have addressed both main questions, which I would like to hear. How do the X1 and the M8 compare, and how does the IQ these cameras and M film cameras compare to the D90.
Anyone have the latter kind of experience?