I'm going to save you from reading the usual fuzz that you can read in every other review ever on Natsume Yuujinchou. I mean, it's Natsume. You already know what Natsume Yuujinchou is. That brings me to the good thing about this movie, it doesn't do anything wrong. It's good because it's Natsume, and if you're thinking about watching this movie, chances are you've already watched the last SIX SEASONS (!!!) that precede it. By this point, you probably like Natsume and know what to expect. What you expect is exactly what you'll find in this movie: the good old usual Natsume Yuujinchou. Describing it asan arc you'd see from the show is perfectly accurate. That’s quite literally what it is, it's an arc in the form of a movie. It’s Natsume. If you're figuring out that Natsume isn't your type of thing after six seasons, I'd be concerned about the fact that you stuck around for so long lol
On the other hand, this movie isn't anything particularly special either, and other than presenting a new story, it certainly doesn't bring anything new to the table. There are some anime movies from other franchises that are utterly elevated from their parent series because of multiple aspects (ex: Haruhi), but I can’t say the same here. I’m not going to say this lack thereof is a detriment, it’s just the lack of something newer and special. Not to say that there’s anything wrong with that, though!