Pathfinder Flip-Mat: "Bigger Keep" [RPG]

At first glance, the Bigger Keep flip-mat is really impressive.  The "front" side is a top-down view of a castle built entirely, I guess, on an island, with the only land access through a drawbridge--pretty secure!  There's a large courtyard, some buildings, and some towers, along with what I think is a central well.  This side could work well if you needed a big "king inspecting the ranks" scene.  It's less useful for a traditional "castle siege" encounter because of the water surrounding it--you'd need some sort of flying or amphibious assault to capture this place.  Some of the problems with this side is you can't see where the doors are into the buildings, it's a bit confusing to tell whether the stairs are going up or down, and it takes som
e thought to understand the different vertical levels in different parts of the keep.  If you stare at it long enough, you can figure it out--but it's not intuitive.  The "back" side is a representation of the interior of the different parts of the keep--there's a mess hall, a shrine, and some offices (oddly, no bunks or barracks).  The problem I had with this side is that it's a shifted top-down view and hard to match up with the "front" side.  The interior of the towers, for example, are abstracted elsewhere--I guess--and there are some rooms that I can't figure out how they're accessible to the rest of the keep.  I can see what the designer was going for, but I just don't think it works well--flip-mats are supposed to make encounters faster and easier, not require puzzle-solving.