This may not be relevant, but Michel Thomas is not the person who is doing the teaching on his discs. It is other teachers teaching but using his method.
I agree that it was a disconcerting when I tried out the Spanish disc just to discover that the native German speaker from the German disc was teaching it. Regardless, these discs are great if you just need some working knowledge of the language. I use them in the car so that my baby can be exposed to the sounds of other languages (not that I expect her to start speaking those languages, but apparently exposure to various sound patterns is good for their overall cognitive development). Plus, I've learned some useful things myself.