[Brightcolours]

The EOS R6 (20mp, 12 fps mechanical shutter / 20fps silent shutter): £2499

The EOS R5 (~45mp, 12 fps mechanical shutter /20fps silent shutter, 8K DCI / 4K 120 fps): £4199

To put it in perspective: The Sony A9 II has 24mp, 10 fps mechanical shutter 20 fps silent shutter, £4800

The R6 basically competes with the A9 II in performance, and the R5 is something else. The Sony A7R IV of course beats it in stills resolution (61mp).

Both the R6 and R5 beat the Sony A7S II as video camera too, apparently. Lets see how Sony will rect with the A7S III.

[toni-a]

Where's Nikon?
They are offering slightly upgraded versions of their current line, while they seem to be aggressively targeting entry level market... On the high end of mirrorless system they seem to be left behind

[Klaus]

I reckon the natural competitors of these two cameras are the A7R IV and A7 III - less so the A9 II.
Canon will surely come up with an R1 at some stage.

In any case, it's good that Sony is finally getting some serious competition at least at the high end.
Canon really needs to work on its offerings for enthusiasts though. There are no sanely priced ultra-wide and tele zoom lenses.

[Brightcolours]

I reckon the natural competitors of these two cameras are the A7R IV and A7 III - less so the A9 II.
Canon will surely come up with an R1 at some stage.

In any case, it's good that Sony is finally getting some serious competition at least at the high end.
Canon really needs to work on its offerings for enthusiasts though. There are no sanely priced ultra-wide and tele zoom lenses.

The A9 II performs under the R6 in data speed and specs, and the R6 rivals the 1D X III in specs. An R1 would have a chunky 1D form factor (with big button areas, integrated vertical grip, extra battery capacity).
A9 II size/weight: 128.9 x 96.4 x 77.5 mm / 678 g
EOS R6 size/weight: 138 x 97.5 x 88.4 mm / 680g

The one thing the A9 has over the A7 III: faster sensor readout of 1/160th of second (other cameras around 1/40th of a second). The 1D X III has a readout speed of 1/60th second, and the R6 probably has the same sensor. But perhaps Canon will disappoint and give a electronic 1st curtain shutter like with the RP?
No, from the specs it is clear it also has a mechanical 1st curtain shutter.
Two UHS II card slots (like the A9 II)

"Leaked" US prices:
R6 : $2499
R5: $3899

85mm f2: $599
600mm f11: $699
800mm f11: $899
100-500mm f4.5-7.1: $2699

[davidmanze]

https://blog.kasson.com/the-last-word/how-fast-is-the-sony-a9-electronic-shutter/

[Brightcolours]

Additional info about the R6 (launched):
It indeed has the 1D X mk III sensor.
Internal video recording at 4K is capable up to 59.94 fps or 1080p up to 119.88 fps in 10 bit 4:2:2 Canon Log(H.265) or HDR PQ(H.265). The camera also features a built-in 0.5-inch OLED EVF with approximately 3.69 million dots and a 119.88 fps refresh rate. Dual UHS-II SD card slots, 3-inch 1.62 million dots vari-angle LCD touch screen, optional BG-R10 battery grip. Can focus in low light down to -6.5 EV (central AF point, f1.2 lenses). AF possible even with a 600mm/800mm f11 lens with 2x extender (f22). Shutter life: rated 300,000 times.

[Brightcolours]

R5: RAW 14 bits burst (mechanical/EFCS): 180 shots. JPEG 350 shots.
R6: RAW 14 bits burst (mechanical/EFCS): 240 shots JPEG 1000 or more shots.

Ridiculous buffering.

[Klaus]

An impressive bunch of gear.
The cameras tick all boxes really. Makes you wonder what could possibly come on top in terms of hardware?
While I admire the R5, the R6 is probably way more significant.
But Canon really has to work on their prosumer grade lens lineup. Or maybe Tamron/Sigma will come to the rescue.

And it'll be interesting to see the counter-reactions.

[davidmanze]

Overall, it's an excellent showing from Canon ....... they are doing in the ML world what Nikon did with the DSLR ...... the D500, the 500mm PF and the D850 ...... the latter two being on back-order for over a year ......

  What a difference a few years makes? ...... I'm looking for a D850 and they are popping up for sale everywhere here ..... except near me ...... they are just going out of fashion ..... 
 
   The question now is, what is Nikon doing? ..... their product sensations of three years ago are now almost forgotten .......

[Brightcolours]

The D850 is an excellent machine, if only it had n AA-filter and EOS mount and I'd be wanting one ;-)
What I find curious is how the D5 and D6 somehow disappoint in some areas compared to the 1D X II/III, where the D850 seems "just right".

Canon did get complacent in their processor development (while being innovative in other areas), which set them back compared to Sony, a bit later Nikon, and even Panasonic (mainly visible in how they implemented 4K (cropping). So, someone at Canon clearly prioritised processor development. I am sure Nikon is working on a new generation of processors too, but i'd be surprised if it would be such a big leap as Canon made.

Can the D850 both be on back order AND out of fashion at the same time?