I have owned and flown an ASW20F for about 5 years. It is the equivalent to the Schleicher A model, built under license by Centrair of France as the F model. It has the same nice flexible wings as the Schleicher A. Very nice for ridge flyers. As far as I can tell there is little difference, if any, between the two. (Speaking of the F model only, not the FL extended wing version).
Centrair support for their aircraft in the USA is almost non-existent in my experience. My understanding is that the Centrair F model was not supposed to be exported to the USA under terms of the licensing agreement with Schleicher, but there are numerous examples here.
Check out the Yahoo ASW20 user group. Lots of good information and files there.

In the interest of full disclosure, my ASW20F (AJ) is for sale right now.