Hi melody. Are you in the UK or elsewhere? If in the UK, the best cages for Chinese are the Ferplast Kios (7mm barred cage) or a Zoozone 1 tank (but the grill at the top would need meshing). There are others on the market to look at but these two seem to be the most favoured for Chinese and for any of the dwarf hamster species.
To answer your question though, the main differences between Chinese and the other dwarf species, is that the Chinese are much better climbers and `cling` onto things well. For ground dwellers, they can look and behave more like mice. They also have the intelligence of mice.
They are shy and curious little creatures but can be bold once they get settled, although taming a Chinese can take time and patience. It really depends on the hamster, it`s age and whether it has been handled a lot.
I would imagine your Chinese would come from a pet shop/store? If that`s the case, he or she might need time, but they are really lovely and I have a real soft spot for the Chinese.
A word of caution though. Don`t be tempted to buy a pair. Chinese hamsters usually end up fighting and fighting badly, so it`s best to keep one alone, be it male or female. You might also consider rehoming one that is already on it`s own.
So the main difference between both would be that Campbells are not as good at climbing as the Chinese, but both love to dig, especially the Chinese, so the Kios cage by Ferplast has a deep base. Both cages can be added to with shelving and a decent wheel and accessories. Chinese love to hide, so they do appreciate egg boxes and little hidey holes!