Tokyo is a fantastic Multi day resort, 2 theme parks both of which can take several days to see.
The Tokyo Disneyland Park (TDL) is based in the original Disneyland Park in California and Magic Kingdom in Florida. It features versions of many of the classic Disney attractions you'll find here like Jungle Cruise, Space Mountain, Splash Mountain and many more, plus several attractions found only in TDL. It's famous amongst Disney fans for hosting the most lavish shows, parades and events of any Disney park anywhere in the world...
Next door to TLD is Tokyo Disneysea. a entirely new concept of theme park exclusive to Tokyo, whist a couple of the rides here are based on attractions from other Disney parks the majority of the park is unique. The Park is often referred to as the most beautiful Disney theme park anywhere in the world, largely because of it's HUGE design and build cost,
Tokyo itself is a wonderful and inspiring city with an amazing varied culture from the super modern to the ancient temple and heritage. In addition to this the Japanese people are IMHO the most welcoming and politest nation I have ever encountered.
Hong Kong Disneyland is, by contrast, still a very young resort. It only has one small park that requires one full day to see. Based on all the previous Disneyland parks, although most obviously inspired (at least in several architectural elements) by the original Disneyland Park in California. Most of its attractions are copies or retelling of those currently on offer in other Disney parks. Its visitor numbers are a small fraction of those found in the Tokyo Parks and this is evident in many areas, from the merchandise offerings to entertainment which is much more modest than that of Tokyo
Hong Kong City is again a unique destination full of culture and unique experiences. Although I feel it offers less variety and quantity diversions. Shopping here however is outstanding and vibrant.
The best answer I can give you is I have told some of my Disney friends You must go to Tokyo, scrimp, save, beg and borrow, just GO! whist of Hong Kong, I generally feel the park still has to grow and mature before I would recommend anyone travelling with the intention of going there as the main reason for their trip.
SW