I find it interesting because Harry and Hermione have most of the knowledge from the books working in their advantage, but not all, leading to some... interesting decisions, from the point of view of the reader, but that make perfect sense and are actually very clever from theirs.
The author isn't trying to make everything go unrealistically perfect for them; instead, we're being treated to the real consequences of their actions, both good and bad, but mostly unexpected, making it a refreshing story.
Their being in the wrong body both limits their movements (Hermione realizes how bad Harry had it during his life; Harry starts to experience discrimination for both being a girl and a Muggleborn) and brings them newfound freedom in how to act (Hermione has the influence of The-Boy-Who-Lived and so people listen to her, and Harry finally gets a real taste of a happy childhood and loving parents, and generally has less stress).
They both decide to be more proactive, so, whether they intended or not, they're attracting a lot of attention everywhere they go.
Possible cons: The constant Pronoun Trouble
in the narrative, when only a few instances would suffice, (SPOILER SPOILER SPOILER SPOILER: Harry and Hermione's decision to use aliases to avoid possible slip-ups of their true identities as body-switched, and the ease with which they convinced the other first years to follow some of their ways of thinking. END SPOILER END SPOILER).
Personally, I think the story is good enough that those are not bad enough to ruin it, but I find them annoying every now and then and I can imagine other readers wouldn't like them very much, since they are all almost constant in the narrative.
Also, the story's pacing is rather slow. Instead of jumping straight into the meat of the plot-points, we are seeing something more resembling a Slice Of Life
story where Harry and Hermione struggle to fit in and worry about their identities and their old lives, while still trying to make progress in making everything go right with their limited resources as young students. If the idea of reading about their mental and emotional struggles bores you, this probably isn't the story for you.