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Those chat modules are ok for a small amount of users, perhaps 10 or 20 at a push, but they will slow your website down.
Flash chat by tufat is probably the better option of the ones mentioned.
If you have cash, want reliability, usability, scalability, then consider 123flashchat its a server based chat room, with an XOOPS plugin to allow direct connection of usernames from XOOPS to chat.
Yeah it costs money, but if your offering a professional service with members chatting daily then 123flash could be your answer:
http://123flashchat.com/if it's just a hobby, and you ain't too bothered, or your just trialling chat then the flash chat by tufat is the option to go with.