I don't have any personal experience with aluminum flywheels, but I stuck with a ford racing steel flywheel because I knew it was going to end up my DD..
I've heard the heavier weight makes DD like slipping the clutch easier with the greater mass of a steel flywheel. Also that launching at say 2,500rpm has more energy to the tires with the added rotational mass. Though I would suspect an aluminum flywheel would make up for that down the rest of the track.
like I said I've never ran an AFW so these are just some things I've heard. But when I question anything I just go with what I know. And steel flywheels work just dandy for a DD