For one, the EOS R appears to have a horizontal-swivel touchscreen -- unlike its Nikon and Sony counterparts, this might work for video blogging. There's also a touch strip on the back that could offer finer control than a dial. And while Canon will make you buy into a new RF lens format if you don't want to use adapters, you'll have the option of a 24-105mm f/4L IS lens that can cover telephoto shots in addition to two primes (35mm f/1.8 IS and 50mm f/1.2L) and a 28-70mm f/2L. Nikon's current Z lenses only include one zoom model, and won't include longer-ranged glass until 2019.
Other details? The camera will reportedly include an OLED viewfinder with about 100 percent coverage, and will shoot at a respectable (though not Z6-level) 8 frames per second in continuous mode. We can already see some caveats, however. The EOS R shoots 4K, but only at 30FPS -- and you'll have to step down to 720p if you want 120FPS. Canon also doesn't appear to include in-body image stabilization, and there appears to be just one SD card slot. Pros looking for dual slots or CompactFlash may have to give this a pass.
If past leaks are authentic, Canon is slated to unveil the EOS R within days, ahead of the giant Photokina camera expo. The main unknown at this point is pricing. It's unclear whether Canon will aim squarely at the A7 III and Z6 or try to undercut them. The high-end lens selection hints at the pricier approach, but Canon may have a tough fight ahead when its opponents have compelling features of their own.