I don't know what your looking for with this thread exactly. An excuse not to use destroyer?
From what I understand:
Destroyer Ochem: Indicative of the real DAT (Know roadmaps, go through at least twice
Destroyer GenChem: Much harder than the real DAT, but if you can do it "cold" as some have put it you will be successful on the real DAT which makes sense but may be more work than is necessary (I.E. go through once)
Destroyer Bio: Mixed bag here. Some breakdowns say that the bio section of destroyer did not help too much, while others say that it hits some of the randomness that is the DAT bio section. If anything I feel that Bio destroyer is a supplement to Cliff's AP bio.
Math Destroyer: On par with the real DAT (some say 60-80% of questions they saw were problem types from the Math Destroyer (go through once untimed, then as many timed as you can on the second time through)
I haven't taken the test yet but i know that destroyer has played a huge part in my DAT preparation--namely showing me exactly where I am weak so that I know what to work on. My first time through studying for the DAT I didn't work enough problems. Destroyer has helped immensely in this area. (Just my 2 cents)