The Clojure example he gives of a closing paren stack that looks like ]))))])))) highlights the downside of the Clojure sugar for vectors. It's a lot easier to just keep pounding out parens at the end of an expression until they match up than it is to carefully alternate ] and ). This outweighs whatever gains were made by the vector literals IMO.

I think I would have preferred some standard reader macros instead for collection literals.