Some very rough preliminary testing shows them to return the same results in a few different file types that I've checked, however in Common Lisp, this is a valid function call/name for a function titled #/something:
(#/something "here")
If the cursor is on the #, it won't find a valid symbol, while it will find the match if using the sexp type (I assume the sexp is just grabbing until the first whitespace.
Granted, this is quite unusual, especially considering CL uses the sharpsign as a way to reference functions like #'symbol-name as well.
Thoughts?