tools.reader, at least the EDN reader part, is more strict about what it allows as symbols, vs. throwing an exception, vs. clojure.edn/read. For example, symbols with multiple slashes are read by clojure.edn/read, as shown in REPL session below.
It seems worth perhaps adding a mention of this to the list of differences near the end of the README.
user=> (require '[clojure.edn :as edn])
user=> (require '[clojure.tools.reader.edn :as tredn])
user=> (def x (edn/read-string "http://www.example.com/FIXME"))
user=> (name x)
user=> (namespace x)
user=> (def y (tredn/read-string "http://www.example.com/FIXME"))
Execution error (ExceptionInfo) at clojure.tools.reader.impl.errors/throw-ex (errors.clj:34).
Invalid symbol: http://www.example.com/FIXME.
Not sure we want to document this, it is undefined behavior for `clojure.edn` to accept it, as the EDN spec explicitely mentions `/` being allowed only once :
>/ has special meaning in symbols. It can be used once only in the middle of a symbol