I use something similar, but I had a bad experience with it the other day. I was trying to scuff an area (already primed) for an antenna doubler.
I had already dimpled the holes and was having a hard time breaking the primer enough to get a good ground. So I went to the heavy duty artillery and sure enough, I removed about half of the dimple. I was heart broken for not paying attention and letting it happen.
I ended up saving it by enlarging the holes from #40 to #30 and putting in a larger rivet. It's still not perfect, but it's something I'm going to have to watch over time for cracks.
The lesson I learned was to be very very careful with when (and how) I use it.
On a side note, the vibrating sander with a scotchbrite pad works really well for breaking the shine on the aluminum. That's something I've been doing for awhile and haven't had any issue with it. Just make sure you dimple *after* the use of power tools. If you don't remove some of the dimple, you'll certainly shred your scotchbrite pad.