My opinion on Destroyer vs actual DAT, as far as difficulty: You will see all very similar, though more straight-forward questions on the actual DAT. But, you should definitely know Destroyer very well because any component of any of the questions will show up on DAT. For example, they had a really terrific question for kinetics where you compare the rates from a table, and THEN they ask you to predict how quickly this reaction will proceed, given what you know, with new concentrations that do not show up in the table. Even though you will NEVER be asked on DAT to do what is in essence a 5-part problem in Destroyer, any 1 component OF that question could show up--and because you know how to do that 1 problem from Destroyer, you will know how to do any 5 questions that could potentially be asked on DAT--this is why it's an extremely challenging, but effective (and in my opinion, ESSENTIAL) tool.