Use what's working for you but one of the strengths of parser combinators is managing abstraction so that you can reason locally rather than having to manage things "ten layers deep." That's more of a problem in imperative approaches where you are manually managing a complex state machine, and can indeed have very deep `if` hierarchies.

Parser combinator are good at letting you express the grammar as a relationship among functions so that the compiler handles the nitty-gritty and error prone bits. (Regexes also abstract away these details, of course.)