How we're viewing this unit is simple... a combination of a really high resolution studio camera (50MP), with the highest speed sports camera (30FPS), all in one, along with 8K video. We don't do video, so I won't be touching that aspect of the camera.
For having had the a7RIV and have the a9ii cameras as current my arsenal, we had expectations, and like some, several doubts pertaining to Sony's claims, and much to our surprise, all that was claimed met or exceeded our needs.
FAST... no not really..., the a1 is LIGHTING fast, and with the proper memory card, the buffer clears up even faster than the a9ii, even with those larger files. We also noticed that the camera "wakes up" much faster, which is a welcome asset when working with multiple units.
We only had the chance to use the "Human" Eye AF, but in difficult situations, such as ice hockey & snowcross, where the subjects had helmets/masks. A big 2 thumbs up for the efficiency. Looking forward to using the animal & bird AF features, once we receive our own unit.
The dual-dual slots... each of the 2 slots accepts both the CF Express type A cards, with contacts facing one way, and SD cards with contacts facing the other, without the risk of inserting them in the wrong way. Smart, and convenient.
Unlike the switch from the a9 to the a9ii, Sony has decided to make the a1 with a9ii compatible components, both the vertical battery grip, and batteries. For those of us with several of each, that's a nice trait expense wise.
The EVF (Electronic View Finder) is larger than on the a9ii, and double the resolution. To honest, it's almost TOO nice, that's how clear it is. One thing that we found annoying on the a9ii, which they fixed on the a1, is when you're wearing a fluorescent accreditation bib, on the a9ii the EVF would be constantly on, and the image would be restrained to the EVF only, unless you'd slightly pop out the screen.
The question we've all been asking... "What about high ISO"? Judging on my comparison between the a9ii and a1 at 25,600 ISO, the a1 is nicer, and considering the amount of pixels, that's a huge improvement.
Since this was a pre-production model, not all options of the camera were activated, but we did successfully try the "tether to cell phone" feature. We think it's important to note that at the time we tested the unit, Adobe had yet to release a Camera Raw update, so all images were captured were done so in JPG format.
After using the a1 in multiple scenarios, our opinion is clear, Sony is now leaps and bounds ahead of the competition. It's time for the two other major players to play "catch up". The future in photography will be interesting to see, but for the time being, there's no other place I'd rather to be, than holding this superb unit. For the type of mandates we do (Studio, Sports & Events), the a1 is a total beast, and ours are on order!
A few sample pics from different shoots... HERE 
