I am in the same situation as you as far as the corn field. Originally, I was planning on burning it, but I don't think it will. Now I am thinking about brush hogging it down and plowing it under. If I wasn't going to plow, I would probably brush hog and then burn. It sort of depends on how much trash that will be on top after mowing. Farm hunters and others will know more about this.

As far as the tractor, I would seriously look at the closest dealers, whether they have mechanics to work on tractors, and the number of replacement parts they have on hand and the owners personality and devotion. Then I would choose one of them. That way if any thing happens to the tractor, you have a close place to take it too, or buy parts from. Any of the name brands generally are good. I like Fords myself, but that is just what I grew up with. The local Ford dealer in my area will come in during off hours if I need a replacement parts in an emergency.