For a hammer drill you stuck for corded?
I tapcon all day with my DeWalt 18v XRP no problem.
For rotary I use the DeWalt naturally.
As far as demo go I use an old but rebuilt Milwaukee, looks like something the terminater would carry, really heavy, very big, but damn can it drive some ground rods in the toughest of hardend clay.
For an auger drill I use a Milwaukee auger drill that was (No lying, will take picture if need be) purchased new in 1982, now 23 years of un-interupted service is pretty damn good, and it has been used ever since date of purchase.