Young

Forgive me for interrupting but I have used both cameras: The a7riii has less rolling shutter, better motion cadence (imho), a better noise reduction algorithm which reduces ghosting outside of the log-gammas and it's easier to pull manual focus due to the better EVF and screen. If you like sharpness in full frame, then the a7iii is better of course, but sharpness is, as we know, a bourgeois concept.

Forgive me for interrupting but I have used both cameras: The a7riii has less rolling shutter, better motion cadence (imho), a better noise reduction algorithm which reduces ghosting outside of the log-gammas and it's easier to pull manual focus due to the better EVF and screen. If you like sharpness in full frame, then the a7iii is better of course, but sharpness is, as we know, a bourgeois concept.

Forgive me for interrupting but I have used both cameras: The a7riii has less rolling shutter, better motion cadence (imho), a better noise reduction algorithm which reduces ghosting outside of the log-gammas and it's easier to pull manual focus due to the better EVF and screen. If you like sharpness in full frame, then the a7iii is better of course, but sharpness is, as we know, a bourgeois concept.

Forgive me for interrupting but I have used both cameras: The a7riii has less rolling shutter, better motion cadence (imho), a better noise reduction algorithm which reduces ghosting outside of the log-gammas and it's easier to pull manual focus due to the better EVF and screen. If you like sharpness in full frame, then the a7iii is better of course, but sharpness is, as we know, a bourgeois concept.

If you need high res then def go for a7riii. The a7riii IS a better camera than the a7iii for video in almost every way (a7iii has sharper full frame 4k). But is it worth the price?....if you only shoot video...absolutely not. If you need high resolution stills....there is nothing on the market that comes close. 
SO if you were buying an a7riii for ONLY video...I would say NO...go for the a7iii. But for both. totally go for it

A rant. I mostly shoot on DSLRs for my work. Got a big yesterday with a Sony FS7, big ass tripod, monitor, the works. Ohhhh fancy stuff by my standards!
But here's the thing. It drove me nuts. Moving, positioning, getting shots was so damned cumbersome. Shot some Broll of a guy on a sailboat.
I garauntee I could've gotten way more and frankly, way better and more interesting content with my trusty GH4 and gimbal. Blah blah specs, I don't care. Footage would've been nicer and more interesting to 100%  of audiences.
I know there'll be some "back in my day, cameras weighed 1000lbs" folks who will scoff, but you know what? Fuck large camera systems. Fuck them. 

D750 is magic. I want it back. 

There is something to be said about the A7III that goes beyond specs – I own the A7III and I own the A7rIII and I used to own the GH5 and after som extensive testing I must say the A7III is lacking. It's a fine camera, certainly at the price point. Small but by no means insignificant things make it less useful to me however. For starters the 4K full frame may be very detailed and sharp, but is plagued by a weird shimmer and a subtle stuttering when moving the camera and it seems to me it has more moiré than the A7RIII, barcode artifacts notwithstanding. I also find that the pixel binned 4K full frame readout from the A7rIII is more pleasant to the eyes and I think it has to do with better motion cadence, less rolling shutter and more efficient IBIS (that 0.5 step makes a big difference in real world usage without stabilized lenses). Not saying the A7III is not a good video camera, but I do prefer the image produced by the rIII. It would be interesting to hear if someone agrees/disagrees. I know the camera isn't available yet in the US, but here in Sweden and the rest of Europe it's been in stores for some time now.

After many test, I decided to keep the GH4 along with the A7iii.
I need something really reliable, maybe with less creativity possibilities, but which will never let me down in difficult situation.
As much I like the A7iii, I can't be sure that if I have some shoots to do outside at 35°, it will be usable. Also, the 4k50p is very helping when you need slowmotion or agressive stab.
Keeping both is expensive, but now I feel good about any work to come.

Unfortunately eye AF only works for stills, but face-detection has been impeccable so far for me in video mode, both with the A7rIII and the AIII.