I wanted to go to the highland because of the haunted house, and I got to see it, it was creepy and awesome, but I had picked a wrong day for it was a national holiday so the lines were very long, I had to stand in a line for around 2 hours to get in. So if you decide to go there, check the date, you should preferably go there on a weekday that has no national holidays to have the best time.
Fuji-Q Highland is simply awesome. The queues aren't so long, the roller coasters offer impressive views of Mount Fuji in the distance and previously held Guinness World Records, the two water rides will get you soaked, even the Ferris wheel is great, but, the main attraction for me was the Haunted House. I won't spoil it, but if you ever visit Fuji-Q, you should definitely pay the extra charge to take part in the scariest adventure of your life.