As to namespaced keywords, I was skeptical at first, and all my spec definitions used unqualified keywords. But as usual, if Rich does things a certain way, there are good reasons behind it, even if they don't immediately seem apparent. As my code base has grown, I found that namespaced keywords make a lot of sense, not just because of clojure.spec. They give you a convenient way of naming things uniquely, which lets you have data structures that combine several kinds of data without worrying about naming clashes.
You don't notice their utility in code examples, or small projects, but in large projects they are very useful.
You don't notice their utility in code examples, or small projects, but in large projects they are very useful.