There are just under 30 people registered on Orchidbids at this point. Anything you list there will randomly be advertised on the OrchidTalk lobby page and if you also list your item in the for sale forum, the likelihood of a sale is just as great as if your item was listed on the forum alone. The only thing that might possibly keep people from buying is their reluctance to spend a dollar to verify their identity and register; however, a person worried about a dollar is probably not likely to buy your item anyway.
Maybe others can give their feedback but that is our take on it. Hope this helps!