i did my first set of holes with the step bit. seemed to burn them out, certain sizes in the bit would get too hot and get dull. you're basically drilling 8 holes to get to the size you need.
i did all my new HLT and BK electric stuff with 2 hole saws, one for the heating element and one for the 1/2" couplers. faster and easier than the step bit, no question. left the edge just a little rougher than the step bit, but i went and cleaned it up with a file or grinding stone and all is well.