Scheme has a Lispy syntax (good or bad depending on where you're standing, but probably not neutral) and doesn't have static type inference, which is the whole point of the article. Haskell is just enormously complex for anyone who doesn't have a very strong background in maths and category theory. Seriously, it's an amazingly cool language, but unless you can look at ST and not feel a little confused at first, you won't be able to shake the feeling that Haskell is smarter than you are.
OCaml is a reasonable middle path. It has a lot in common with Haskell (H-M typing, ML syntax, pattern matching) and is largely pure, but doesn't absolutely force purity on a language level the same way Haskell does. Strictness is the default, with laziness as an option, so there are no surprising space leaks. IO is performed with IO functions, not with some bizarre monad that is the description of an action that would be performed.
OCaml is a reasonable middle path. It has a lot in common with Haskell (H-M typing, ML syntax, pattern matching) and is largely pure, but doesn't absolutely force purity on a language level the same way Haskell does. Strictness is the default, with laziness as an option, so there are no surprising space leaks. IO is performed with IO functions, not with some bizarre monad that is the description of an action that would be performed.