I got it the day before yesterday and went out yesterday to test it at my 'happy place'.
Here is a selection of images, shot on the Canon R6MkII, hand-held, available light, seriously downsized in PS to post, with default lens corrections and some cropping.
Red Panda@10m: R5, RF 200-800@ 600mm, f/9, 1/500sec, ISO-6400 
Emu: 481mm, f/8, 1/500sec, ISO-2500 
Emu: 300mm, f/7.1, 1/320sec, ISO-800 
2xStick Insects: R6 RF 200-800@200mm, f/7.1, 1/160sec, ISO-6400 
Stick Insect: 200mm, f/7.1, 1/40sec, ISO-6400 
Gouldian Finch: 570mm, f/8, 1/250sec, ISO-6400 
Cockatoo: 570mm, f/8, 1/250sec, ISO-6400 
Cotton Top Tamarin: 800mm, f/9, 1/500sec, ISO-6400 
Kakariki: 570mm, f/8, 1/400sec, ISO-6400
Takahe: 570mm, f/8, 1/640sec, ISO-400 
Ring Tailed Lemur: 227mm, f/9, 1/250sec, ISO-2000 
Brolga: 277mm, f/7.1, 1/320sec, ISO-500
Serval: RF 200-800@800mm, f/9, 1/500sec, ISO-6400 
Serval: RF 200-800@ 311mm, f/8, 1/400sec, ISO-5000 
Serval: 250mm, f/8, 1/320sec, ISO-2000
I was particularly pleased to get three shots of the Serval (the cat). It is reclusive in any case, but because it has incredibly good hearing - it can hear a mouse underground- it is inclined to face away from humanity because we make so much noise.
Overall, I was very impressed with the performance of this lens.
cheers, TREVOR
The mark of good photographer is less what they hold in their hand, it's more what they hold in their head;
"All the variety, all the charm, all the beauty of life is made up of light and shadow", Leo Tolstoy;
"Skill in photography is acquired by practice and not by purchase" Percy W. Harris
