I have got an iPhone 12 Pro Max today (my 1 year old son broke the screen of my iPhone X), the box is the size of a VHS tape.
There is a small manual and a lightning to USB-C cable. The iPhone 12 Pro Max is bite thicker than previous iPhones and the back facing cameras are quite big compare to the cameras in the iPhone X.
The iPhone 12 Pro Max is little longer than the iPhone 8 Plus, as you can see on the photo below.
The sides are straight like the iPhone 4 and 5, the front looks like iPhone 4 scaled up.
The setup went smoothly: contacts, photos, apps are synchronized from backup and my Apple Watch got paired directly.
FaceId and Apple Pay had to be setup again since the information is stored locally on the device.
It took a photo in a dark room, the quality was excellent!