YMMV, but I find the readability of J and K to be far worse precisely because of the ASCII charset instead of the glyphs. The APL glyphs give me a concrete context switching mechanism that I'm operating within its "alphabet" and the semantics thereof. Whereas because I associate ASCII characters with plenty of other meanings already, I find J and K to look like complete line noise in comparison.
Would have to be a one to many relationship. Part of the problem with K is that the meaning of an operator depends on the type of the operands. "?" can be "generate a random number" or "search for an element in a list" for instance. And yes, that is insane.
