I agree with this. I had five cameras in Italy this summer and used four quite extensively, including a DP1M and RX1 and the somewhat less detailed Nikon A and still less detailed Fuji XE1. When processing them and zooming in on parts of the image, the DP1M was absolutely amazing - a revelation. The RX1 was pretty close in that regard. The Nikon was still good but not as good and the Fuji lagged a bit behind the others. It was obvious when pixel peeping while working on the the shots. But once I either posted them on the web or printed them for the book I put together (11x13 pages), the level of detail in the shot was really irrelevant. The character of the photos, the way the lens rendered, the colors or tonality of the B&W, etc, was still prevalent and there were notable differences. The Fuji shots had that smooth creamy look, the Sigma was a bit crunchier for lack of a better word, the RX1 just had some certain magic I can't describe, and the Nikon was just dead competent on every shot. But the resolution and detail simply didn't matter much when viewed in those ways. And as amazing as the Sigma files were to work with and as great as the detail was when looking at 100%, it just didn't matter under normal viewing and I didn't like the fundamental look of those shots as much as those from the other cameras. BUT, when it came to things like DR and low light, those differences were more apparent even in the printed shots, and the difference between the RX1 and everything else, particularly in really low light, is NOT subtle. It's my first experience with full frame in a digital context and I'm way past impressed and its generally what I reach for in low light except those times I just happen to have the Nikon with me. And it's what has me interested in these full frame bodies, particularly if I enjoy shooting them with manual focus glass...I just don't think that this is consistently the case, and not at web resolutions such as 1024 or 1600 pixels. The Sigma Merrills in particular are cameras that I have researched with the thought of owning one myself.
One of the big realisations relating to cameras that has formed in my mind is that once a certain level of technical competency is reached the differences in output from one camera to another are subtle at best and are more subject to personal taste than an extra half stop of DR or some extra lines/mm of resolution. The problem with technical image quality is that it isn't linearly proportional to aesthetic image quality.