I've been around here a little while and I think it's a pretty fair statement to say that lot's of us are biased toward what we own -- after all that's what we decided on for some reason, be it the dealer or the machinery.
At the same time, I don't think there any "plants" posting here from one brand or another. If there are, they're pretty good at what they do. Kubota and JD are the most popular brands on this site. I think that's a reflection of market share among the CUT consumers mre than anything else. When you get into the bigger tractors, there are not too many posters but they are pretty well balanced out with JD being the most common.
Personally, I think JD people are the most brand loyal. I know the farmers around here who use JD tend to be pretty avid about it. The guy who rents from me collects the things, has JD hats, shirts, decorations in the house, signs on his truck, etc. I wouldn't be surprized if he dyes his hair green some day. /forums/images/graemlins/laugh.gif
Then again, the place I ordered my tractor from sells Case, Cadet, and Kubota. The guy I worked with readily admits that he has a personal feeling that tractors should be International Harvester Red. He'll happily sell Kubota's and sells more of them than the Case, but he prefers sell Case just because they had red tractors on his farm when he was growing up and that's what they run now. It would be interesting to know how the Ag companies managed to develop such fierce brand loyalty among their customers. There are probably more than a few auto execs who would pay to know the secret.