Views differ, but personally I don't like to think of strings as aggregate collections of characters (but then, I also don't really like the character as a data-type), so using 'is seems conceptually simpler. It makes sense to me, as often as I bandy about strings and compare them, that 'is treats them as a simply-compared type. Granted, they are not. It's something I guess I've gotten used to by using symbols, as drcode points out (yay, link to a post in the same thread!): http://arclanguage.org/item?id=7965. To each their own.