I would recommend PMs for the negative responses because everyone tends to really remember the negatives when they hear it. That's not fair for the bowyers.
Once when I PM'd a guy about a bow he bought, I got a pretty bad story about a high-profile bowyer here on TradGang. Complete with pictures and a detailed explanation. I won't take a chance with one of those bows, but neither will I name that bowyer in a public forum. It's just not fair. And everyone makes mistakes... even a good bowyer. It's like accusing someone of molesting children... once the accusation gets out, they get labeled, whether guilty or not. And it is of little use for that bowyer to try to defend himself or his work, because the damage has already been done.
Oh, and it was not one of the two mentioned in this the thread, either.