I have both regular destroyer and math destroyer and I'd say they're both pretty similar, but math destroyer has a more comprehensive list of formulas and slightly more variety in their problems (ellipses, logs, graphs, and intercepted arcs, to name a few). Overall, math destroyer is great for extra practice, but it has several of the same type of problem (like combined work problems show up multiple times), so it's pretty much like getting practice solving the same problems that are just worded differently.
But I haven't taken the DAT yet so I don't really know how they compare to the real thing 😛 Anybody done with the DAT want to shed some light on this?