I started a thread on this, but as this one has taken over, mine is now redundant and I have deleted it.
"Nikon Z8 is announced: price $3997 in USA and £3999 in UK. The UK and US prices are basically the same as 20% taxes are included in the UK. Kudos for Nikon for not price gouging the Brits, and so it's £300 cheaper than the R5 for us. I hope Nikon is successful and keeps up the competitive pressure. It looks like a great piece of kit with the performance of the Z9 but cheaper and considerably lighter."
The Z9 is a really good camera but is as big as a tank and weighs about the same. The Z9 has an AF that is as least as good as the R5, and if the Z8 is as good, as it should be, Nikon now have an excellent rival to the R5, which is still larger and heavier, but more up to date in some respects, but not enough that would tempt me back.