As usual people prefer to learn a language from a native speaker…
I do have to say that I prefer learning a language from a bi-lingual or more lingual teacher. Why?
Because native speakers most of the time don’t have a feel for the difficulties of their language, nor as for the cultural differences revealed in the language. Which is my advantage when I go back to Malaysia to teach French: I can add the cultural differences and point them out where they are hidden in the language.
For instance; if the French have 1001 words describing the weather, it means that weather is:
- an important subject to start a conversation
- quite diversital
Anyway, if you really want to see some cultural differences, seen from an English teacher in Japan : the latest site added to the Add your link directory has a lot of cultural clashes with beautiful pictures though and podcasts: Of Rice and Zen talks about the cultural clashes from a westerner teaching English in Japan 
