How do those touting Exmor advantages demonstrate them? They underexpose by 4-5 stops then push the shadows back up. While there are valid reasons to do that, it's an 'advantage' that's totally useless to the vast majority of dSLR buyers.
A lot of people do just that, yes. However, I have been showing examples where underexposing was a necessity. I'm an "afternoon landscaper"...I can never get up early enough in the morning (which is really early, like 3:30am), in order to be able to drive out to the kinds of beautiful landscapes I want to photograph, but get there in time to set up and be ready to go by the time the rising sun lights the clouds afire with color.
So, I'm stuck taking my photos in the afternoon, when the setting sun washes the clouds in color. Problem is, all the mountains are to my west, same direction as the sun. Even if I keep the sun itself out of my frame, I'm still trying to photograph scenes with MASSIVE dynamic range. It isn't under-exposing if your trying to avoid clipping the highlights.
I was just out again today, trying to find some good mountains with colorful sunset clouds (largely a bust...the clouds just never got colorful). Anyway, it's always the same problem for me...every landscape has massive amounts of dynamic range. Even WITH stacking three GND filters (Lee 0.9, 0.6, and 0.3, or 3, 2, and 1 stop...that's SIX STOPS of GND filtration, and it still isn't enough!!) When you stack that much filtration, if the clouds are still bright enough, or if you have any kind of uneven horizon (usually the case with mountains), you end up with an inverse gradient to shadow...the mountains get darker and darker as they get higher.
I haven't done landscapes in a while...but nothing's changed now that I'm shooting them again with the 5D III. I'm not underexposing my shots by 4-5 stops....I'm exposing for the highlights. I always bracket, of course...but, all the problems still exist...the inverse mountain gradients when using GNDs, the massive amounts of scene DR. These are real-world situations where I'm encountering too much DR for Canon sensors to handle, and it's proving to be a hell of a lot of work to merge an HDR that doesn't have posterization problems around the bright areas, doesn't have motion ghosting problems around wind-blown grass and trees, etc.
With two more stops of sensor DR, or to be more specific...with two more stops of shadow-lifting ability, with a sensor that has read noise in the deep shadows that has a nice random appearance without any banding of any kind, I could probably get away with my GND filters, some hefty shadow lifting, and one single shot...instead of bracketing 5, 7, 9 shots and having to deal with some frustrating HDR mergers. Things aren't quite as bad when I'm west facing east at sunset, or east facing west at sunrise...however, even in those circumstances, many of my older shots, taking with my 450D and 7D, still have problems with detail in the shadows...those cameras still have 11 stops or less of DR. Having two extra stops would have meant I could pull out much cleaner, more colorful detail from the shadows.
I'd really be curious to know, how many people run into the same situation? I've been spending a lot of time browsing through landscapes at 500px. There are a LOT of people who photograph landscapes. I think landscapes might be 500px's largest category.