I've been using these sounds a lot. For the kind of music I make they work really well. Many atmosphere sample packs just have flat samples of the sound and rarely add much to a track. These are nice organic sounds which are layered really well and evolve through the course of the patch. They allow you to easily add dynamics to the atmospheres in your music without hours of work.
Also, when used in a sampler, they allow you to mute the separate layers which is useful if there's a part of it you don't like or you just want to simplify the sound.
Using them for me was really simple. I just copied the sampler patches to my sampler instruments file and they popped up in logic. These are a specific sound which may not be to everyone's liking, but if you are making dark music or soundtracks you will love them.