After much deliberation I took the plunge and bought the R5. I have only had it a couple of days but I'm extremely pleased with the performance after an extremely limited trial.
When I added the Canon 5D4 to my 1DX2 stable, I was more than impressed with the added technology the new body came with, it's a similar case with the R5 which goes a step further again. After abandoning my 1Dx2 in favour of the 5D4 for some time, I eventually returned to the 1DX2 because when it came down to it, I just preferred the images it took.Will I find this to be the case with the R5? Time will tell but sadly the 1DX2 has to go as age has caught up with me and as I head in to my 8th decade next year it's time to shed the pounds if I'm to carry on in this absorbing hobby for many years to come.
For a while I swung towards the R6. It seemed to offer everything I needed, including the reduced weight but at the end of the day, the few extra features of the R5 swung it , particularly the 45mp sensor.The R5 of course is a lot more expensive and I have already realised the cost mounts up beyond the purchase of the camera itself. You need an adapter to use your EF lenses, a CFexpress card to take maximum advantage of the video and high fps rate.Then you have to decide how to transfer your images. The CFexpress card readers are expensive, but I have been happy not bothering with a card reader for my other two cameras simply downloading straight from the camera to the computer. You can't do that on my computer as I don't have the needed USB3 port so I will have to buy either a card reader or a USB3 to Thunderbolt 2 adapter. The little expenses are starting to mount up!
Then there is battery life to consider. The R5 has so much extra technology it does chew battery life and I haven't even attempted video yet. Lots of functions can be turned off of course and I could opt to buy the battery pack but then the weight saving starts to vanish and so does the bank balance.
Currently there are no must have RF lenses that I desperately want although I'm tempted by the RF 800f11 as a lightweight walkabout lens or for air travel where baggage weight is a consideration. The RF 100-500 comes with not only a hefty price tag but some serious limitations ( and another hefty price addition) if you but the teleconverters to extend it's reach. No, I'm more than impressed with the EF-EOSR adapter and it performs as promised with no compromise in image quality or AF performance. I did opt for the control ring adapter version which was more expensive than the standard one but it's use is very limited to me unless I have the outfit tripod mounted.The ability to hold everything safely and twist the control ring , especially on a longer lens, is nigh on impossible.
One of the things I really like about the R5, and presumably the R6 is the reticulated screen. I love the fact that not only and you can avoid the direct sun preventing you viewing the screen as it can often do on a fixed screen in "live view" but when you want to put it away in the camera bag the screen can be turned inwards to protect the surface of the glass. The screen though is also my biggest worry, time will tell but I think there will be more damage to users screens due to the delicate hinges.Care is needed!
My final observation is the layout and controls. It's brilliantly thought out, and another swing to the R5 over the R6 for me. You have most essential things at your finger tips but there is the rub. Small size and weight comes at a price. This body is more suited to the slender female hand than my stubby fingers but that said I'm managing OK. A slightly bigger body, would be an advantage to me and might also help cure some of those heating issues too..