TDS: crazy busy . yes.
but absolutely the best theme park in the world.
fully immersive with some incredible rides (20,000 leagues, Journey to the Center of the Earth, a very unique version of Tower of Terror, it's just an amazing park)
as for Nagashima Spaland? a do not miss. .it's a "greatest hits in the world" park. They travel and find rides they like, then bring them there.
So they have an EXCELLENT RMC (Hakugei), the longest coaster in the world (Steel Dragon2000), a Manta Clone that's way intense (Acrobat), and S&S freespin that spins more than any freespin in the world (Arashi), TWO Schwarzkopf (a Looping Star and a Shuttle loop), an Ultra-Twister (last one operating in the world?), a 1st Gen Intamin Drop (Freefall), a decent mine train coaster, and a bunch of other smaller coasters. . that doesn't mention some great flats, and a walk thru haunted house thats just amazing. There's so much more than the water (ie: Spa) section of the park.