The Hawthorn strainer is for the metal side of the Boston Shaker, a Julep
strainer is for the glass. Thus you'd use a hawthorn strainer for a shaken
cocktail, a julep strainer for a stirred one.
Two, Four prongs, slots, slats, etc... all just different designs of the same
thing. I haven't found any specific benefit/reason for one over the other,
although I prefer a four prong.
-Robert Hess
www.DrinkBoy.comwww.MuseumOfTheAmericanCocktail.org