Yes Kilin Parrots are worth owning, as for the ones Petzone sells its hit or miss. Some of the ones they have are really nice and others are complete garbage.
Treat them as you would a Blood Parrot, although they might be a bit more aggressive. As long as you are getting true Kilin Parrots with the Blood Parrot shaped mouth they can't cause much damaged to other fish. What other fish would you be putting them with?
If you do decide to buy from them request a picture of what they have instock before your order because the pictures they have are out of date.