An even more efficient interchange is the roundabout interchange https://en.wikipedia.org/wiki/Roundabout_interchange
The only problems with the roundabout interchange are that you need two different bridges spaced a distance apart which can add construction costs and they require more area than a standard interchange, although about the same as a clover leaf.
Edit: On second thought I'm not entirely sure that is a double-diamond, although I've heard people refer to it as one. It doesn't seem to match up with the wikipedia article, however.
I take it all this extra complexity is just to avoid roundabouts?