You should see a performance boost in the Haskell implementation by compiling with GHC's LLVM backend[0]. Another Haskell ray tracer ran 30 % faster than the native codegen this way[1].

[0]https://gitlab.haskell.org/ghc/ghc/wikis/commentary/compiler...

[1]http://blog.llvm.org/2010/05/glasgow-haskell-compiler-and-ll...