[davidmanze]

for a do it all camera that's not not likely to go out of date!

"not likely to go out of date" --> rather unlikely: tech is getting out of date quicker and quicker ;-)

     It's Sony's personal tech which will take a few years to equal ........... and it doesn't come cheap .......


   I suppose 30 fps will eventually seem pedestrian  ..... or perhaps the colour black will go out of fashion ......

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   Sadly the body size stays the same ........... the key points are the frame rate in ES and the refresh rate (240 fps) with a 1.5X increase in sensor readout speed ...... ie. tracking fast objects will be closer to real time ......
 
......... giving an experience more akin to an OVF ........ yay!


  ......... Sony unfortunately are limited with their mount which is small for a FF MLC ..... limiting the Ibis's ability for movement ...... hence they implement slight crop for their super stable movie  modes (cropping out the dark corners) ...... maybe one day that mount will come back to haunt them?

  All in all it's a massive upgrade in every department ..... ....

  Some are complaining at the price ....... I think it's reasonable for a do it all camera that's not not likely to go out of date!

You are probably right about the IBIS being limited by the very narrow mount. But especially in the video IBIS implementation Sony probably could improve things with better algorithms? The difference with the R6 and R5's IBIS is night and day, at least in video. Also Nikon appears to do a better IBIS than Sony with IBIS + OSS https://www.youtube.com/watch?v=DKKaw7B3LVU

I don't know if I can see a difference between 120Hz and 240Zz refresh rate with OVFs, I would have to try that. I do know that I have little issue with the (lower) refresh rate of my MacBook Air or even EOS M (back LCD), but with EVFs I find earlier Sony EVFs unusable, and even find the few 60fps EVFs I have looked through "restless". I have not tried to look through an EOS R5 120 FPS EVF yet (due to corona).
I do see that the high EVF refresh rate setting (240Hz)of the A1 lowers the EVF resolution to the R5 and A7R IV EVF resolution, similar to what that A7R IV does when set to its high (100Hz) setting.

I do find the price a bit high, compared to a Canon 1D X mk III, Nikon D6 (those have expensive bodies, expensive OVFs/prisms, expensive PD AF sensors/optics/electronics/mirror assemblies) and Canon EOS R5 and Sony A7R IV. I find the price of this Sony A1 a steal though, compared to a Leica SL2-S

 I don't think algorithms will save the corners of the image ....... Sony is forced to crop ..... no thoughts of ibis in those days ....their mount is a physical limitation ......

  Visually you won't see much difference between 120/240 fps .......  it's not there just for smoother motion but for fast moving subjects such as BIF/ fast sports ....... coupled with with a higher read out speed using ES, the subject should be more or less in the same place in the taken image as when you panned  it in the EVF ......... for the same reason Canon's sports camera will be using global shutter ... (and probably the same refresh rate)
 
  ....... btw, apparently the R5 only uses 5.6 million dots when reviewing images in the EVF ......... and drops down when shooting ......... ( stated by Chris Nichols DP review) ........... which is why I was puzzling over why Nikon's EVF got as much praise as it did being a lower rez display.

 ....... when sports shooting in high speed mode at 240 refresh fps with a 600mm + TC frankly I doubt if you visibly see the drop in EVF rez ........everything will be whizzing past so fast ........ but it's there for astro, portrait and landscape.

   Leica yes ...... still using one focus point only in their MF range ....... you still have to focus / recompose .........

....... in terms of expense the major one of course is R+D plus a few latest chips not forgetting heat dissipation components ...... buy a QXD 240 Gb memory card for instance .... makes a OVF prism look like a bargain .....