I have a friend who is deeply into modern static-typed languages (Haskell and OCaml), but has worked professionally for a couple of years in Clojure. His big gripe with Clojure is that it's still dynamically typed, and thus vulnerable to type-based uncertainties. In languages like OCaml, lots of bugs are actually syntax errors and will be caught at compile time.
On the other hand, Clojure is at least a functional language. You get the benefits of immutability, no side effects, higher order functions, etc, in a neat and understandable package. And it runs in the JVM and thus has access to the bazillion or so libraries written in Java, thus getting around the interop problems that other modern languages (and some older ones) have.
Has your friend used core.typed[0]? I haven't really, but I've wondered if it might be the perfect balance for people who really miss their type system.
On the contrary, I came from Haskell-land and was impressed by Typed Clojure, at least in that it is capable of representing some things that are not easily represented in Haskell types. For example, union and intersection types can be pretty powerful. They can have easy variadic functions, and the occurrence typing is sweet -- after a runtime null check, it will remove the `Nil` type from a type union within the if-branch, or a runtime collection-empty check will modify the type in the subsequent branch to no longer include a case for a possibly-empty sequence.
On the other hand, Typed Clojure does not offer nearly the cohesive experience one gets from Haskell, nor do the types guide optimizations etc. Type checking is really a lint step rather than a build step. And almost all existing Clojure code is still dynamically typed, so you can't usually infer how to use a lib based on its type signatures (since it doesn't have them), which I love being able to do in hs.
On the other hand, Clojure is at least a functional language. You get the benefits of immutability, no side effects, higher order functions, etc, in a neat and understandable package. And it runs in the JVM and thus has access to the bazillion or so libraries written in Java, thus getting around the interop problems that other modern languages (and some older ones) have.