Very rough cuts only... I added it for the bit about using it on fiberglass, as one of the previous posts mentioned. It's great for plastics and fiberglass...
Even on aluminum, the coarse teeth don't load up as quickly, a bit like a vixen file...
But for the aluminum cutting, I prefer to use the Dremel with the 2 inch Tuf grind disk, followed up by a 2 inch fine sanding disk in an angle die grinder to "sneak up" on the final line.
Large holes in sheet are easily done this way too... just use a Unibit in the corners, and the Tuf grind disk between the corner holes.. clean up with the angle die grinder and a 1/2 inch Dremel sanding drum in the corners.
This technique can be seen in this repair I did recently on a Grumman Cheetah...
http://www.bondline.org/index.php/An_Example_Repair
gil A