the "wow" factor of the Magic Corner, you notice there's a lot of mechanism required to make it work. Does all that hardware take away from the storage of the corner?
Using Sketchup, I drew each cabinet and the surface area for the Magic Corner and the Lazy Susan. Then using the area calculation function of Sketchup I was able to determine how much actual storage area there was on any given level and compare it to the entire area taken up by the cabinet on that same level. Believe it or not, this sort of thing interests me.
So the Lazy Susan is the winner, right? If we were comparing only efficiency, then yes. But we also need to factor in efficiency of the actual storage shelves and how they fit into the layout of the kitchen.
The biggest issue I have with the Lazy Susan is the fact that it's round, and the majority of the items I want to store on it are not. I've lived with 2 Lazy Susan cabinets in my kitchen for 10 years now and there's a lot of wasted space on those shelves. It's not bad, but in comparison, the square shelves on the Magic Corner are easier to work with. They're also adjustable and removable which provides a nice flexibility.
A typical Lazy Susan cabinet will be 36" x 36" which means you have a fixed amount of space you'll be taking up along a wall. This often means you'll be using a filler (or custom cabinet if you have access to them) to get the run of cabinets positioned the way you want ... centring the sink beneath a window for example. The nice thing about the Magic Corner is that it uses a "blind cabinet" (sorry, more cabinet talk) which can be pulled a variable distance along the wall. Flexibility is a big plus, especially in renovations.
So do we have a clear winner? It will all depend on the kitchen and the person it's for. But if you base it on what I see being built in our shop, the Lazy Susan needs to go back to the gym and do some more training.