The smaller hammer force of the hammer drill is for lighter duty work. A mason or tradesmen that needs to drill 3/8-inch or larger diameter holes in masonry, drill through rebar, or break up concrete will use a rotary hammer (or larger demo hammer). But the hammer drill could be the right solution for use around the home or for light carpentry. MRO (maintenance, repair, operations) professionals also love hammer drills for drilling numerous 1/4-inch or smaller holes for periodic Tapcon installation. The hammer drill will likely be less expensive than the rotary hammer, but it is also less versatile. It can be used for wood or masonry whereas the rotary hammer will accept bits for hard clay, tile, chiseling, and more. You might find the hammer drill being knocked off course by heavy aggregate while the rotary hammer will drill steadily through concrete.