Most of my punts have been with WG's who have AW profiles and have made bookings through that. All the punts I've had when the booking has been made "official" on there have been positive experience, so I've always at least left positive feedback with a short comment.
I've done a few FR's, all of which have been overwhelmingly positive, although admittedly some are from experiences whereby, nowadays, if I had around the same quality experience, I wouldn't quite be as quick to do that unless it was particularly special and/or with a WG I've seen for the first time.
That being said, I've found I've enjoyed typing out the FR's I've done, memories of the experience flow back as I type them which is enjoyable!
Has anyone seen a WG through AW who has insisted on NOT making the booking "official" via AW? I would take it as a sign that the WG is afraid of being given negative feedback because she knows she's providing a below par service and hoping to get away with it.