I have had good luck with step drills and we use them quite often, specifically when just cleaning up holes cut on our cnc plasma.
A few years I found this
http://www.mcmaster.com/#4080a26/=r1d6zv It works well if you are trying to drill a hole from nothing, I do recommend using a drill press for this, as it can still walk out like a regular hole saw, but the finish is much better.