Thank you for using links on this site to buy—and FYI if you sign up for availability notifications by B&H, this doesn’t give credit to this site. Get Canon EOS R at B&H Photo.
A few lenses are lacking, like a fisheye, 11mm to 15mm range, and super-telephotos. But the existing Canon EF super-teles can be used with the Canon Mount Adapter EF-EOS R, so that’s not a serious issue. And there are some unique offerings, like the ultralight Canon RF 600mm f/11 and Canon 800mm f/11.
In short, we now have a 35mm full-frame mirrorless world where Canon and Nikon and Sony and Leica and Panasonic all have highly credible mirrorless systems—terrific!
None of these systems all have pixel shift and multi-shot high-res mode and focus stacking support, though the Panasonic S1R has multi-shot high-res mode and focus stacking support and thus gets high marks. The other systems are a WTF situation: for example it is inexplicable why focus stacking support is not available for Sony and Canon. And none of them have any form of ETTR metering.
In most regards, Sony mirrorless retains a substantial lead, with a far wider lens selection along with resolution dominance, and so it remains the go-to system for most. But some of those Canon f/1.2L primes are spectacular and may be compelling for things like portraiture (or simply spectacular lens performance).