A big part of it is the fact that Scheme is simple and Common Lisp is not. This is a "soft" feature, but I think it's important. I want to try out Scheme and see if it feels better.

I ask because I'd like to get a perspective on the tools that are available from people who actually make things with them. The programming language I use might be a "secret weapon" in some situations, but most of the people it would give me an advantage over wouldn't even understand why it's an advantage.