Jim, if you are going to drive ground rods with any electric hammer, use an attachment.

The repair on the heads are expensive.

We actually use demolition hammers to drive rods, not rotary drills.

As far as good overall Rotor hammers, we have Bosch, Hilti, Hitachi, Makita,and Milwaukee and they are all dependable if maintained.

So I would say out of these, shop for price and warranty

Roger