I feel as though they are largely rubbish in this area now (I am near Reading, so get some interest from Portsmouth/Southampton sometimes). I have been punting for 7 years and most of my bookings were through RBs for most of that as I found them a good way to screen potential new people, at a price I was happy to pay. I had some excellent meetings at significant discounts from quoted rates.
But now all you get is the same old faces who can’t be bothered reading what you are asking for, reply to every RB, don’t fit the age profile and don’t offer the services you want, or ask for twice as much as you’re offering. I still post RBs occasionally but the last 5 or 6 I have not gone ahead simply because no one suitable replied.