These types of shootouts generally only work when there is some type of "control" piece in the shootout. Something that everyone can familiarize themselves with, like a SM57. Something that everyones heard. Even then you can only judge based on the differences between the given samples, which in the context of a mix is only marginally helpful. You really have to be at the shootout to get really good intel from it by comparing the results to the actual source in the room with your own ears.
The one that always makes me laugh is the converter shootout. People will post samples of Apogee, Lynx, Prism, etc and then ask which one is best. Then you hear the usual remarks about how one converter sounds more "mid-forward" than another converter or some such nonsense. How do you know that converter is "mid-forward" and not the mix. Maybe the "mid-forward" converter is most accurately representing the analog source. And without hearing the source in the room, the whole test is bunk, even before you drop it down into mp3 land.
I find the "tell me which of my setups is best" type shootouts are generally just a result of a lack of confidence. Either in their gear, their ears, or their ability to decide what they actually like.
And then to top all this off, many of the people making comments about the shootouts, saying things like "Apogee's are a more coloured converter" have only ever heard an Apogee in an online shootout, and never actually ran signal through one. They just spout off what ever the masses say about gear X this month.
At the end of the day many many of the best records produced today use Digidesign 192 converters, which according to the unwashed masses, should only be used as paperweights or to keep a mic stand from tipping over.