wow...just thinking about that makes me want to include RoC in my first playthrough when FTB 1.7 comes out. It's ridiculous to get a return on the investment Using IC2 or TE to make the HV arrays I found. But the way I manually mine, fully processing 8 stacks of ore doesn't seem ridiculous.
You should see what the extractor does with Nether Redstone Ore. It's something like 45 redstone per ore.
I completely ran myself out of redstone autocrafting some HV arrays. Popped over to the nether for 5 minutes grabbing the rather common redstone ore. Came back and ran it through my extractor, and I had more than a 256x256 quarry got me