Catches with OCaml? Mutable strings, unchecked integer arithmetic. It's got its fair share of ugly corners.
Just a casual observation of the commento-sphere after a lay imperative programmer's cursory research of functional programming. This post, sample-of-one hugely notwithstanding, seems in the absence of counterpoints to suggest that, as potentially narrow as the benchmark may be, Ocaml has some very strong arguments against Haskell on the compiler implemenation front.
I can't help but wonder if this GC outperformance is the flipside of the coin of Ocaml's much maligned lack of multi-core capability.