Essentially, the programs that are installed in the Delta chip are the same as for the standard Diablosport chip. Therefore power gains would be the same. The advantage of the Delta chip are being able to have 2 programs and the third being the off or stock mode. This is great for testing, as you would not have to remove the chip to change programs. This is useful, say if you decide to run nitrous or would like to try 2 different programs in a forced induction application and so on.
In many cases, the standard chip would suffice.