What are your experiences with language schools?

I’m interested in taking a short, two-week, French course in France, but there is just an absolutely astonishing number of schools available, with very little information regarding personal experiences.

So for those of you who have taken intensive language classes, how did you narrow down your selection? How did you determine if the school was any good before leaving?

Regarding France, information there would be helpful too. I’m looking for a place other than southern France since I’ll be spending some extended time there later in the year.

It really seems strange to me that there are so many languages and language schools for each of them, yet there is so little information regarding them. Surely they can’t still be around if people don’t go to them.