Yes, I used them and found them fairly good. We did the retreat method and took longer than they recommended but that was our choice.
They were very supportive of us and didn't try and force us down any particular route (although at the time I felt they were keener on controlled crying than other methods but didn't force us in any way and allowed us to do what we thought was the best).
We really needed the outside support and they certainly did help us with that.