I ordered a 28mm Crescent Root (http://ift.tt/1Jhc9rj) French hotel to see if they are as nice in person as they are on their Web page. They are. These are MDF buildings that come pre-painted. Some sections are pre-assembled, and other sections can be easily assembled and disassembled.
First, the paint job is superb — significantly cleaner and more detailed than other pre-pained buildings, such as 4Ground or Miniature Building Authority. The doors are all attached with a simple tap hinge that works well enough and allows players to open and closed doors during a game.
In this picture you can see the brackets in two of the walls. Small pins fit within the holes to hold the walls together. They slide in and out easily, and they hold the walls at right angles.
Here you can see the pins inserted into the brackets.
If I have a complaint with the building it is that the floors fit too snugly. I think they will be difficult to removed during a game. Shown is the attic. The second floor will be difficult to reach during a game, I think.
This building, 28A3 is among the more expensive ones, at about $90. It is one of the most elaborate ones. Others are cheaper. I think the enhanced quality is worth the premium price. I see myself order one of these a month, until I complete the set.