I looked at about eight pages of the specifications...looks pretty good in terms of specifications. I was impressed/glad to see that it can shoot to multiple capture formats: Full-frame at 3:2 aspect, APS-C at 3:2, and also 4:3 aspect, 16:9 wide-format aspect, and also 1:1 aspect ratio, AKA square. Very nice in terms of the possible capture formats. At times, the 3:2 aspect ratio is just "too wide", or more often "too tall and skinny", as in when photographing people in the vertical format--that 3:2 aspect ratio is just, well, too tall...or too skinny...or both! 5:4 or 4:3,either, can be better for single- and two-person portraits in a lot of cases. And also, being able to capture to different aspect ratios can make having one lens, or one zoom lens, much handier. Sometimes one WANTS to shoot on an APS-C type camera, not an FF type camera. Square? That too can be pretty nifty on some subjects.
I like the idea of 30 megapixels at the FF, 3:2 aspect ratio. Thirty megapixels sounds pretty good to me...more than 24, fewer than 36 or 45.
I suppose that over the next week the camera specifications will be endlessly discussed on the www. From what little I have seen, just specifications on-line, it appears that the camera ought to be at least good.
Better than the Nikon Z-series Z6 and Z7 models? I do not think that would be too awfully difficult for Canon to achieve. Canon has good marketing skills, so I think they'll probably do okay with this offering.
I really do NOT think that I would buy a first-generation mirrorless from either Canon nor Nikon; Sony's A7R models had some issues in their first incarnations, but those have largely been rectified now, now that they have hit the III (third) generation.