1. The feel is great. Finally! Sony listened to us shooting sports and PJs. We wanted a bigger camera the same size as the a9, but had more beef with grips, buttons, and better weather sealing.
2. Anti-flicker is finally coming to a9II! For us shooting in a less desirable place covered with dark, dimpy, flickering light, you just turn on anti-flicker and a9II Automatically senses when you need it and does it. Simple is good!
3. I love a9 for everything except shooting with a strobe. The a9II has undergone a major upgrade with a mechanical shutter, so it has the same -10 fps full AF tracking as the a7r IV.
4. Mechanical shutter ragtime is a thing of the past - this sucker shoots right when you want it and is just in time for the basketball season!
5. Real-time tracking, a9 gave us It's more accurate than the one, more mature and calm. You can literally hit people with arms and legs, and the a9II finds faces, eyes and rocks, so all frames are working on the eyeballs, even if it's an athlete. The EVF has an improved resolution, but uses the same speed / refresh rate as the a9. The image quality is so good that I find more eye relief.
6. The 1/200th sync speed is 100% solid. In the past, some of the FF bodies have fluctuated in terms of how they sync regular studio flash units at 1 / 200th. Often you need to drop down to 1 / 160th to make sure the top of the frame is really clean. This really influenced me for strobe hockey where you get "dirty ice" on the frame.
The a9II doesn't yet have a 1 / 250th sync like a professional camera, but it can count at least 1 / 200 days. I have tested with Dynalite, Orlit, Prophet, and Erinchrome using the Sync Pocket Wizard and 1 / 200th is safe. Most important to me is the additional processing power of the a9II. I'm certainly looking forward to the new features that Sony will add in the near future - this will add value to the camera over long distances.
I thank Sony for making these FW updates free and allowing me to do them myself on my laptop!! Finally, I still love the a9, but I will use the a9II from my main body. I'm a Sony sponsored shooter, but these words are my own. A9II is a tremendous gift for photographers who choose to use the best.