Ive argued for and against this argument of handling, but I will say now, that my experience with the Leica Q is that it really is such a joy to behold, and joy to use and in many ways is a digital M body that the digital M's just are not (to qualify; all of the digital M bodies are physically larger than the film M's and though this might seem picky, it matters to me). The Q on the other hand seems refined and possibly where id jump off the Leica M film train and into Leica Digital. Its a logical step as far as Im concerned.
As far as the Sony is concerned, well I think that most of the established master photographers out there go, they have pretty much either expanded out into other 35mm equipment or abandoned Leica completely, so Sony will probably pique interest for them.
I could well imagine, that whats been delivered here (if the IQ is solid, obviously), this camera will be picked up on by a lot of serious photographers, especially in the fields of journalism and documentary work), I wouldnt be surprised is in 5 years time a handful of interviews with masters will reference this camera as being a part of, or indeed the only camera they are/were using at the time. Similar to how the Fuji X100 series has done in the last 3-5 years or whatever.
I see this is, logically, a strengthening of an already existing milestone with lots of refinements and lots of innovation without much risk for either Sony or the user.
I think its going to be a big hit. If I had the money to buy either a Q or this, I would have to have them both for a week to find out.