Fuel consumption is always a tough one because there are so many variables that can't be controlled in the "real" world.
The biggest variable is load. At 100% load there's not much difference. The Diesel will actually use more fuel because it has a larger displacement. You will seldom be at 100% load however. At anything less than 100% load you could probably give an edge to the diesel. In either case there probably isn't much difference.
Traditionally it's been said that the EFI will get 10-15% better fuel economy than a carbureted engine. That is about what they say for a diesel engine vs. a gas carbureted as well.