ReHIPS, judging by some of the posts here, is not very well understood. I served as a beta tester for several versions of ReHIPS, including the current one, and I can tell you that the primary feature of this software is isolation of vulnerable apps, such as browsers and Office suites. This feature is a little bit like Sandboxie but stronger.
It "also" has a strong HIPS component, but that is not the highlight of this software.
It is designed for advanced users.
ReHIPS has a demo version that may be used without time limit. However, it is hard to run multiprocess browsers in isolation with the demo version.
You may run the full version of ReHIPS for free in a virtual machine if you get the appropriate key from the forum.