State of the Common Lisp Ecosystem
<p><pre><code>   The fact that it’s built on Emacs is a problem, as telling a new user they
   have to learn Emacs before using SLIME (which is not strictly true) is a
   significant artificial barrier to entry.
</code></pre>
Yes, it is true.  It's ridiculous to expect a person new to a language to also learn Emacs.  It is absolutely a significant barrier to entry.