CLOS-like object system with full multi-methods allows more flexible object orientation. All types in system participate in inheritance hierarchy and can be extended by new generic functions and methods. Methods can be specialized on any arguments and to abstract types that might be completely user defined using any boolean expression on real types.
Distribution includes many libraries for common tasks. For example:
dfsch is designed from ground up with integration in mind. It's easy to extend by C code and embed in C applications. C-level API and native dfsch code is mostly identical in capabilities and thus C and dfsch code can be mixed in one application in almost any way that is convenient for programmer.
In contrast to many Lisp implementations, dfsch is perfectly usable for scripting use.