Universal Studios Osaka is great for older kids and those young at heart, especially for roller coaster buffs. While I have been to Universal Studios in the States many times, I have not been to the one in Japan and I was exceptionally excited as they have Wizarding World of Harry Potter. I read all the books at least twice and watched all the movies so this was a definite highlight for me - and for hundreds of people that day.
While not huge, the entire span from castle to Hogsmeade was pretty much true to form. Though we didn't take the rides, I heard from my friend it is pretty exhilarating! At least, I got to try frozen Butterbeer, which tasted like caramel root beer. And I can still remember how sweet it is =)