YMMV but for what it's worth I became frustrated with smartparens when I couldn't figure out how to do something very simple. I think it was traversing down into the next sexp. I got different behavior when my cursor was right up against the sexp versus one space before.

Also whereas paredit really pushes me to have a mental model that the lisp source code forms a tree (e.g. up, down, left, and right being the main operations), I found smartparens drove my mental model back to treating the code a string of characters.

Parinfer is another good attempt at making editing Lisp code easier: https://github.com/shaunlebron/parinfer