It's fine. I quite enjoyed it. It's indistinguishable from the other Ju-on movies in everything that matters, but they've thought up a new backstory and they're doing some interesting things with how the different plot threads interleave. It's basically a reboot, but I don't mind that and it wouldn't be impossible to fan-twist the internal continuity into a sort of inheritance.
Ju-on is one of the two big J-horror franchises, of course, the other being Ringu. (They got a crossover in 2016.) This is the tenth instalment of the franchise, including three Hollywood films, and I've enjoyed almost all of them. What makes Ju-on so sequelisable is the simplicity of its premise. It's about a haunted house and the ghosts who live there: Kayako (mother), Takeo (father) and Toshio (young son). You don't see the father as often as the other two, but then again what he did probably wouldn't make them get on too well. These might also be the most murderous ghosts you've ever seen. They kill everyone who enters the house. There might be one or two rogue exceptions who survived, but I'd have to scour the films for them and I bet they'd have gone mad and gouged out their eyes or something. You'll be allowed to leave the house... but after a while, you'll start seeing or hearing weird stuff. Each film is thus basically a sort of linked anthology of spectral serial killings, with each plot thread having its own unlucky protagonist.
You could go on doing this forever. Ju-on has never been a 1980s slasher-style production line, but it's turned out quite a few good, solid scary flicks based around this premise. They'll usually end up being about Kayako, Toshio and Takeo, though, so I can understand the urge to do a reboot for the sake of being able to say something new about our core ghosts. (This film's new backstory is fairly twisted and involves a sort of Toshio inheritance. Apparently some Ju-on fans have been unhappy that this film focuses more on Toshio than on Kayako, but I didn't have a problem with that.)
This film's (temporarily) living characters include:
1. Child welfare officers. They've come to check up on a boy called Toshio, who they suspect isn't being looked after properly.
2. Toshio's new teacher at his primary school. She's a replacement for the old one, who she's told is absent for personal reasons. She visits the house, obviously, and the really freaky thing is that she meets and talks to Kayako. Toshio's mum offers her tea. This is not a good thing.
3. Four schoolgirls. Some of them didn't want to enter a haunted house, but they got dragged along by the other two. Among the things they find there are some childish drawings in crayon that everyone laughs at while calling "creepy". I need to go back and rewatch that bit, because I think at least one of the girls dies in a way that was foretold in the drawings.
It's good, solid Ju-on. I enjoyed it, as I've enjoyed all the other Ju-ons. I don't think it's really that different from them, or at least the Japanese ones anyway. It's playing around with the details and the backstory, but that's fine. There are spirals, which could be called a loose similarity with Ringu. (One of the lesser-known Ringu sequels is called Spiral, although that wasn't even the only Japanese horror film released around then called Spiral. Different Japanese titles, though: "Rasen" vs. "Uzumaki".) There are some nasty sound effects. We get taken back into the ghosts' old lives, back when Toshio was an ordinary boy with a baby photo album and a toybox. There's a wacky ending that perhaps goes a bit over the top with oogie-boogie and some potential time loop stuff that I'd have to think about, but might almost work better if the dates didn't make rational sense.
If nothing else, it's a better franchise reboot than Sadako 3D was for Ringu. There are two more films in the series, Ju-On: The Final Curse (2015) and Sadako vs. Kayako (2016). I'll be happily watching both.