So let me be clear, these are my FIRST first impressions. Like right off the bat stuff. I've barely even messed around with the camera. The battery is on the charger (it came completely drained) and I don't even own any E mount glass yet (my first lens is coming on Tuesday, which is when the camera was scheduled to be here as well, but I got it early). So this will be simply first impressions of the camera body, controls, build quality, etc.
About me: I'm a professional commercial, event, and wedding photographer who makes 100% of his income from photography. I primarily deal with corporations. I also dabble in model and fashion work for fun (no pay).
So here goes. I will be making a few comparisons to my Canon 5D3 which is my current primary camera for professional work. The first thing I checked on this camera was the joystick. I have been eyeing Sony for a really long time but one of my deal breakers is not having a joystick. You may have seen my thread where I went from being super pumped / sold on the Sony a99ii to no longer being interested. Main two reasons were lack of Sony loyalty to A-mount glass and many reports of shotty craftsmanship in the joystick. Well rest assured that the a9 joystick is up to par. Testing it side by side with my 5D3 joystick I prefer the a9. It's stiffer, the nubs are more pronounced, and the center button is "clickier" with slightly more travel. Granted I am tested a 5 year old + camera joystick vs. a brand new one, and all things considered they are almost identical (minus the nubs). So that's a tip of the hat to Canon's build quality. BTW, I'm not sure exactly how old my 5D3 is, I bought it second hand, so it may not be 5 years old. But it's to be seen if Sony's joystick will stand the test of time. Joystick gets 5 out of 5 stars (as of right now).
Next thing I checked were the ergonomics. This is the biggest argument traditional DSLR shooters (I'll call them traditionalists from here) have against the Sony mirrorless system. I was one of them. I try to never openly make personal attacks against other camera systems, but up until the a9 I knew Sony mirrorless would never work for me due to the ergonomics (remember the joystick thing?) and battery issues. I do have to say that the ergonomics are better than I expected, but not perfect. The camera is shockingly comfortable in my hand. Way more comfortable than I thought it would be. I bought the grip extension (and the battery grip but it's still on its way) and with the grip extension this thing is a dream in the hand! After holding it for just a few minutes, then picking up my 5D3 I already much preferred the Sony. The 5D3 grip feels unnecessarily fat and the weight feels like it will break my wrist. Without the grip extension the Sony would be too small, but it's perfect for my large hands. Reminds me of my subcompact pistol. Once I added a Pierce grip extension for my pinky to join the party, that gun became a dream to shoot. All is not perfect with the grip extension though. I wish they would have made the bottom more level. It is curved on the bottom which makes it awkwardly lean while put on a table. It is not stable at all and would easily fall over if prompted. Well see how it does with some glass on it as well when it comes in. Will I still love the grip when my fingers are losing major real estate while rocking huge G-Master lenses? We'll have to see. The new implementation of the dials is fantastic. I've seen in videos online that some people have said the dial on the left is pointless (with the different shooting speed modes and focus modes). I disagree. These are some of the things I change most often on my 5D3 during a wedding or event. I am a bit worried that in low light I won't immediately know which setting I turned the dial to, but the white on black on the dial does stand out very well, and checking the screen for confirmation would still be quicker than on the 5D3. Having to light up the top LCD in low light and then change focus modes is a PIA. Next we go to button and dial placement. Everything is not perfect here unfortunately. While most buttons feel like they're where they should be, some do not. I'm not a fan of the front dial placement. I wish somehow they could have put it on top like the Canon dial (one used for SS). It feels very cramped and awkward to get to. I want to use my shooting finger to turn it but my middle finger is in the way. I want to use my middle finger but it's the one primarily gripping the camera and it no longer seems secure. And that's with no glass on the camera. I'm sure it will be worse when adding weight. So as of right now ergonomics get 4 out of 5 stars because my only real complaint is the front dial. I've long thought the ergonomics of the Canon 7D (passed on to the 5D3, 4, and 7DII) were the best on any camera ever, and the a9 (while better than any Sony mirroless before) has not swayed that opinion. EDIT: Just btw, because I'm sure some of you were wondering, the lack of buttons to the left of the screen does not bother me. I only ever used the playback button, delete button, and zoom button on the 5D3 (rate and picture style were pointless to me) and those are all easily accessible on the back of the a9. No issues there.
Custom functions: If any non Sony mirrorless user complains about the lack of ergonomics on Sony mirrorless, you can guarantee that one of the first things a Sony user will respond with is, "You can customize the whole camera. Any button can do what you want. You're just not customizing it to how you like it." Well, if there are any Sony mirroless users of that mindset could you please kindly tell me your secrets? Because unless I'm missing something, my 5D3 blows the a9 out of the water in custom controls. For what it's worth, I think most buttons and dials feel like they're in the right spot with the right function already on the a9, but there are a few changes I would like to make that I couldn't figure out. First, I would like to move the aperture control from the from dial to the back rolling dial (the one with disp and ISO on it). It does not appear to be an option. All it's letting me do is reverse which dial uses SS and aperture. Besides that I think all the buttons right out of the box are very well thought out as far as functionality goes. Most do what you would think they should for the place they're at (at least coming from Canon). But if you go to the custom function menu on the 5D3, it is fantastic. It shows every button on a diagram of the camera, and let's you change the buttons to almost whatever you want. The Sony, for all the talk by Sony mirrorless users about customization, is quite lacking (unless there is some user error happening). I was expecting much more. EDIT: I found out how to customize all the buttons, including turning the back rolling dial to aperture. It was slightly un-intuitive at first, but after finding it out, I have found that there is almost unlimited customization. Customization gets 5 out of 5 stars.
Build Quality: Feels solid, but it's no Canon 5D3. I would not trust it in the rain (or even a drizzle). Mainly because of how much it just hurt my wallet, but I've been out in the rain with my 5D3, and while nervous, I was still willing to do it. I don't think I would be willing with the Sony a9. It does feel well made though. I have no complaints about any of the buttons, dials, switches, or flaps. All feel pretty robust and very well built. If I were to come up with anything, the lens mount release button feels a bit spongier than I'm used to, but that's not a real complaint as long as it can do it's job. Build Quality is 4 out of 5 stars.
Autofocus, battery life, EVF, back screen, IQ, and video: N/A. Will add more when my lens comes in. The only lens I purchased to far was the Zeiss 35mm f2.8. It will be here next Tuesday. I wanted something small to take on vacation next week. This lens will probably not be part of my professional setup (I basically just use a 24-70 and 70-200) but will be a great lens for travel. The lens also has great IQ so should do well for IQ and video tests.
I used my a7rii in rain few times, zero trouble there 
