she's done something here that you don't get to see in published fiction very often--she's got two first person POV characters alternating chapters.

You don't see it very often because it doesn't work. Even if someone has the skill to pull it off, and manages to produce a good story, that's in spite of the alternating first person POVs and not because of it. A first person POV should be consistent; alternating POVs should be third person.