Optical Limits is one of the most trustworthy and least biased and pushy of all the sites. I like the throwaway line at the end about the IS: Whether you can really achieve the claimed efficiency of 5 f-stops may depend on your personal saturation with coffee but we didn't reach that in real life. However, it's very good nonetheless.
Interesting comments in the review about Canon not joining the trend in MILCs to introduce automatic image corrections in-camera. He seemed to prefer that, because it means he gets to test actual results from the lens rather than semi-corrected versions (which will always look better on the graphs). It looks like a very good lens, although I can't justify moving from my EF 24-70 f4 IS - at least partly because it is a decent macro lens as well.
Interesting that Optical Limits says the RF 24-105 is a step up from the EF version, but TDP rated it only about the same. From photos I’ve seen online I could believe it’s better than the EF versions, although Canon’s MTF charts suggest there really isn’t (shouldn’t be?) much difference.
Would be interesting to see a Lens Rental review of the RF version. Hopefully that will happen one of these days.
Problem with nearly all of these sites that despite their good intentions or otherwise they generally look at just one copy of each lens. The exception of lensrentals points out that copy variation within a make can be greater than the difference between different makes.