Boone, ED-E (yay companion limit exploits!) and myself destroyed the Giant Radscorpions in that one pass where they are all clustered. In fact, I didn't really do much of anything. The two of them slaughtered them before I could even bring up V.A.T.S. the majority of the time.
I'm playing Normal and not Very Hard, so maybe that's the difference.
Oh on VHHC they can handle a rad scorpion, but not 5. Haha, I learned that the hard way.
"My way of joking is to tell the truth. That's the funniest joke in the world."