I agree with boomana's points on the matter, though I think there is an additional issue. I've noticed on head-fi that certain amps also seem to receive some sort of official status, sometimes as a particular pairing with a headphone, or sometimes as some sort of default for a particular price point or application. When I see this happen, it's not even clear to me that everyone recommending the amp has even heard it and, even if they have, it's also not clear if the person has a particular large amount of experience.
It may be the nature of forums of this sort that people tend to either hold themselves out as authorities, or at least give the appearance of such; I'm not really sure. I do find, however, that it really cuts down on how much help people can effectively get out of recommendation threads, and it does tend to saturate the discourse with only positive reviews.