From a long-time Lisper (Common Lisp, and now Clojure): not, this is not comfortably readable.
That said, I very rarely write code like this. I tend to split operations over multiple lines, so that you don't spend so much time digging into and out of nesting levels. Prefix notation is not ideal for reading math. People have been writing infix math notation libraries for CL for exactly this reason.
It's not a showstopper, though. Also, I do find that sometimes having + and < to be of arbitrary arity is really convenient and makes for nicer code.
That said, I very rarely write code like this. I tend to split operations over multiple lines, so that you don't spend so much time digging into and out of nesting levels. Prefix notation is not ideal for reading math. People have been writing infix math notation libraries for CL for exactly this reason.
It's not a showstopper, though. Also, I do find that sometimes having + and < to be of arbitrary arity is really convenient and makes for nicer code.