The Grudge vs. Ju-on
Saw them both, and I liked Ju-on better, as the time frames and story line progressed systematically and the arc over time was much smoother and made more sense. The plots were different, and I thought Ju-on was more realistic in a sense as the characters behaved as (ir)rationally as you might think they would. What didn't work for either movie was that the ghost didn't follow any rules, per se.
In each, whoever entered the house would eventually die, but the methods seemed to be amorphous. In The Ring, by contrast, we learned that the victims died of a heart attack caused by extreme fear after they had watched the video and not passed it on to anyone within 7 days. Simple, easy rules. Grudge and Ju-on were a bit confusing as to the methods of death, and there didn't seem to be any way out once the person crossed the threshold.
Grudge and Ju-on used the same house and many of the same scenes at the beginning and end, but Grudge failed to match the sense of linking characters that Ju-on possessed. Ju-on had a policeman that had retired early after the case of the people that had died before the new family, and his daughter and her friends were beautifully woven into the story as they saw each other in the house, her grown up, just before he was to die in 'his time'. Ju-on masterfully switches at that point to the future, to the grown daughter and to the roles of the other survivors as each are hunted down after such a long period. Grudge tried in a different way to link Gellar's character with that of Pullman's, and though it was done rather well, it didn't make as much sense to the story.
The time lines were easier to follow in Ju-on as the movie told you which character the next scenes were about, and though not in chronological order it made the most sense from the perspective of events relating to the house. Grudge told us more about the motivations of the cursed family and as to how they were killed in gruesome detail, but Ju-on's subtle deliveries with essentially the same information made the movie scarier as each layer was peeled away as new characters revealed a little more of the evil puzzle. Grudge hands us big chunks as Pullman and Gellar meander through the house 'together', revealing the stalker mom and jealous dad and retracing all of the hints of the aftermath.
What got us thinking was what about all those cops swarming the house taking pictures and such? Did the entire police force jump over balconies, or were they to be stalked down at age 65 when the ghost catches up to them? We know the real estate agent got it, but what about the home inspector, the appraiser, the contractor and designer that fixed up the place for sale? Rules for the ghosts' activities and revenge were never defined, and this was the most troubling part of each movie for me.