I did. There were just some "minor" mistakes in BOS and YUL, but they were resolved very fast after just one phone call.
On all other occasions the program weorked extremly well. Contacting the WbR manager at the location directly got me rooms the very best rates, rooms even when officially sold out and a very nice gift at my last birthday.

The "awards" offered to you via email are way too "US centric" and way too limited (time AND location)