Chris Marshall: David Ellsworth is credited for developing the sweeping grind profile on bowl gouges, hence the name "Ellsworth grind." It's the first change I made to my favorite bowl gouge when I bought it, and I don't regret it. I think it gives the gouge a much broader range of cutting action when turning away the insides of bowls and makes the tool less prone to dig-ins. David is still actively teaching woodturning -- both in demonstration and in hands-on seminars. If you ever have the chance to see him in your area, by all means do it! I attended one of his lectures once, and it was fascinating.

Tim Inman: A brand or a method? Both -- although the "magic" is in the profile of the cutting edge and the geometry of the grind that makes it. The Ellsworth tools are M2 steel, so they are a fine tool to buy. You can make your own and use their grind if tool making suits you. I make most of mine. I use "drill rod" for the stock, and grind out the "hollow" of the gouge and, of course, the cutting profile on the ends. I just like making my own tools. If time and materials costs were factored in, I'd probably be ahead to just order one!