Well, if you're purchasing for a buisness, although it's to some extent true for personal use as well, I'd take a long hard look at the dealer and the tractor. Determine exactly which features you need in both.
Do you need a dealer that is happy to send a guy out to the site to fix something, or are you happy with them telling you to bring it in? How long can you wait for parts -- that is, is the dealer very well stocked and how fast can they get parts if they have to order. These kind of questions can make or break a business because you're going to start relying on that tractor and when it's not working, you may be losing customers.
What brand of tractor are other businesses in your area using? This may say something about the tractor and something about the dealer who supports them.
There can be terrific arguments about tractor quality and cost on this board. Is this brand worth the extra money or not, etc. But if you're saying you have no plans to ever trade this tractor in, then you're going to have it for the rest of your life. Think about that. You also want the dealer to be there for the whole time too.
On the other hand, if you've got good mechanics working for you, or you are one yourself, there are some very good deals out there on China imports and the like. And they are pretty good tractors once you get the bugs out. You just have to worry about a little more downtime.
I am a little confused about Farmall (which is really New Holland) being included in the list you gave of tractors you've been warned against. If you were warned by locals, this list may be dealer issues rather than tractor quality issues.
I have never set eyes on a Kioti, Iron Horse, or a Montana as there are no dealers in my area for any of them, so I can't say from personal experience, but there are a lot of vocal Kioti owners on this board who I am sure will be glad to help you with whatever you'd like to know about them.
Cliff