I agree with all of Stephen Hackett’s very positive iPad Air review, including his points about the cover.
The new cover doesn’t have any points of overlap, and the iPad Air can come detached if typed on too hard. In the vertical orientation, the tablet feels secure, but I’ve had it tumble over backwards on more than one occasion while using it in bed.
In short, the new Smart Cover is a step backwards.
I know the old cover’s metal hinge left scratches after a while but it also provided a much more secure attachment. And the new cover’s polyurethane binding lets it twist. I use the Smart Cover for protecting the front of the iPad Air and putting it into a standing position for watching something or using it for reference. But I don’t rely on it like I did the old cover.
Complaints about the cover aside, I think the iPad Air is a leap forward for the iPad even bigger than the Retina screen.