From the author's description:
1. Flexible templates
CL-Project supports more parameters to embed, by using CL-EMB to represent the skeleton files (See "cl-project/skeleton/").

2. One package per file style (Modern)
A modern CL project should be in accordance with some rules. For instance, one file must have one package in it.

3. Recommends unit testing
Modern projects should have some unit tests. CL-Project generates a system for unit testing, so you can begin writing unit tests as soon as the project is generated.