I think marc really hits the nail squarely on the head here.
I don't know if anything anybody has ever told me, or anything I've ever read, has ever had any lasting positive effect on the decisions I've made about digital equipment. In fact, looking back I'd say it was always misleading to some degree, and was as helpful as it was harmful, which is understandable because opinions are always personal preferences, mixed with experiences, multiplied by subjective circumstances, divided by luck and or misfortune.
Everybody sees differently, everybody has a different disposition, different tastes and different expectations. It's actually quite amazing how much and how deep photographers get into personal nit picking discussions on things like color depth, gradients, bokeh, resolution, corner sharpness, etc. and everyone else on the planet is shooting 99% of their pictures with an iphone.
It really disturbs me sometimes when I notice how obsessed I am (as everyone on this board seems to be) with picture quality and light, and then, like today, I look at the cover of the April edition of the German Vogue, shot by Peter Lindbergh with a Panasonic GF1.
The models hair looks like a black helmet with blotched, blocked up, crizzly digital artifacts for hair. It also looks like it was cropped because it's like not even remotely sharp or detailed. The pic itself is quite nice, very peter lindbergh like, b&w, natural looking light, etc. but my god, talk about a total disregard for "the right tool for the right job". It's almost like the guy purposely said to his assistant: "screw these ***holes, give me the panny, who do these idiots think they are anyway? They don't know what a camera is, sh*t, most of them have never seen a real print before...to hell with em."
Seriously, how big can this guys balls be anyway? The cover of Vogue! We're not talking Terry Richardson here, it's not the look he was after, it classic lindbergh, right out of the 90's but with total disregard for quality. That blew me away.
Anyway, back to the subject, I've never shot the Leica S, but I've used Phaseone and LS glass extensively, and they're good. Everything over 50mm is really, really good. Good enough for me anyway, and I don't see how the S lenses would do anything more for me...the Leica body might make a difference, that I can see, but the lenses, even if they are better, they wouldn't make much of a difference in my work because I don't shoot things that show nano differences in micro contrast or corner sharpness of brick walls. But having said that, I'm sure if I had the Leica I'd say the same thing about the LS lenses, because I'd probably be happy enough with the S glass.
But in the end, you have to judge for yourself, because like everything in life, consensus is usually boring drivel and useless to boot.
Here are a couple of low res. highly compressed, jpegs, shot with a Phaseone IQ160 and LS 80mm and 110mm (left to right).