On the other hand, doors are a more traditional advent calendar concept and there may be a big savings in one's own assembly time and holiday-related labor if they are completely assembled in the factory.
I purchased advent calendar
4155 Christmas in the Forest at my local Fred Meyer store simply because it had the new system of doors instead of the little boxes. I wanted to see how it was put together and see if it was easier than the "old" method. You still must put the cardboard dividers in the advent calendar "body" and place each of the toys in the appropriate space. It comes with an instruction booklet (as in the past) but it also has a little picture of which piece goes in each space printed in that space. I'm not really sure that it's any faster to put together and I have some doubts about how easy it is going to be to open the door and get the toy out without taking the calendar off the wall. (Assuming that you do hang it up and not just lean it against a convenient pile of blue boxes that sit around my house on all horizontal surfaces.)
I wish now that I'd taken some photos of the set up before I got it all together. I didn't put the tape on it yet to hold it closed so if anyone would like a photo of what it looks like inside with all the cardboard dividers in place just let me know and I'll see if I can get it to pose for me.