Hey there. I've only just recently been made aware of this AW feature being re-enabled too. So I've just placed a bid for this Sunday on there. My experiences of using this :- 1) You stipulate exactly what you want from your chosen provider 2) I mention in the bid, that I want the SP to comment, add suggestions of their own, to basically commit and entice me to accept their bids, 3) For those that don't, i just leave out, 4) You can view their profiles, feedback and field reports to formulate a decision.
I haven't had that many in the way of bad experiences with using the Reverse Booking system, in fact I prefer finding new SP's this way.
Anyway, whatever you decide and with whom, i wish you happy punting.