I recently had an email exchange with a friend and fellow Canon shooter about acquiring a Sony AR7M2 for landscape shooting.  I spent some time thinking about it as it is also related to my "search for the holy grail" of high image quality with significantly less weight.  As some of you know I have Canon big glass and pro bodies in my kit as I travel the world photographing wildlife.  Here is the email:

"Hi Steve,
I got your question on messenger and thought I would give it a longer response.

I own the AR7II and an A6500 along with several lenses.  Here are my thoughts:
I think Sony sensors are excellent.  I believe they are generally regarded as industry leading and I would subscribe to that view.  The 42MP’s in the AR7II produce stunning files.

Here are the reasons I have some Sony gear.
Image quality - check.
Weight - with f/4 lenses - check.  With the newer Gmaster f/2.8 lenses the kit is similar to Canon, which while it makes sense was disappointing.  
Camera and menus - the mirrorless cameras are ahead of the mainline manufacturers with innovative features, but lag them in the user interface.  I find the Sony’s to be not as easy to learn or remember.
EVF vs Optical viewfinder - The added information (like real time exposure and histogram) along with improved resolution overcome my preference for an optical viewfinder.  The new ones are very good and I have come to like them.
Action photography - fail.  When the mirror goes away the sensor must provide the data for focusing.  While this has improved dramatically in the past couple of generations they aren’t close to my 1dx2, in my opinion.  And, the other factor that is frustrating is the fact that while the data is being read from the sensor the viewfinder goes black.  This is another area that has improved significantly but isn’t yet at the pro DSLR level.  Easy to lose a fast moving subject.  As you know, the Canons burst so fast you hardly notice the mirror going up and down.  
Landscape - Perfect.
 

So, for a landscape only shoot the Sony system is great.  I would bring the 16-35 f/4, the 24-70 f/2.8 and the 70-200 f/4.
If it was mixed shooting, wildlife and landscape, I would either bring two systems or my Canon gear.  Usually, the latter.
As you probably know, you can buy a metabones adaptor to connect your canon lenses to the Sony body.  Works great for the shorter lenses, up to say, 70-200.  A good way to get into Sony to see if you like it.

As an aside, weight was a big factor for me in looking for an alternate system to either replace my Canon or supplement it.  I thought Sony would be that but it isn’t. In addition to the above thoughts, they are lacking the long lenses.
So, I have been trying the micro 4/3’s from Olympus and Panasonic.  The bodies and lenses are interchangeable.  The new OMD EM1M2 from Olympus is getting high marks from reviewers.  I haven’t tried one but will be.
And, the cost of pro level M4/3 gear is a fraction of Canon or Nikon.  
To give you a feeling for the magnitude of the difference, a typical kit for Canon, like you or I would have taken to see the spirit bears, for example, fits in a Gura Gear bag and weighs 32 pounds.  An equivalent M4/3’s kit with the same focal lengths and speed of lenses fits in a medium size camera bag and weighs 12 pounds.   At this point, I would still take my Canon kit to the Spirit Bears, but maybe not with the next generation of mirrorless.  We did a 10 day  Baltic cruise last summer and I carried Panasonic GX8’s with a few lenses, carried two bodies in pouches everywhere and am very pleased with the images. 
One final thought.  The smaller sensors are getting really good.  When I think that the biggest print I ever make is 16x24, and most of the images go on the web, I’m not sure that having better image quality in the files actually makes a practical difference.   I don’t think my photography will be celebrated in the library of congress so maybe other factors like fun, comfort, etc.  should bear more weight in the decision making than the web reviewers give credit.

So, I think the world is changing and old farts like me with bad backs will be able to extend our adventures a few more years.
Hope this is helpful.  If you have any other questions, let me know.

Mike

PS:  I know, I suffer from GAS (Gear Acquisition Syndrome).  I have come to believe it is untreatable so have just accepted…."