At the same surface, I've found that the DDT and Phaze II hook the same number of boards. However, the DDT starts hooking earlier but is lazier on the back end than the Phaze II. The DDT is quintessential smooth while the Phaze II has back end punch not found in too many symmetrical solids.
Ultimately, there are times when either/or is the better choice. However, you cannot step down or step up to either/or. The ball motions are too dissimilar.