Most of us like the brands we own or sell. LS guys say they are best, I like Mahindra, Kioti fans are loyal, etc. The fact of the matter is that all of these brands are good machines, and of course Kubota is the leader in sales in the USA in smaller tractors and they are quality.
With a budget of $12k, you can get into a new SCUT or close to it, like a Mahindra eMax22. But I suspect you might prefer a size up, like the Max26XL or even better the 3016. But then we are over $15k or maybe over $17.5k depending on options and which tractor you pick. I'm being a little vague on pricing as there are a lot of variables, I'm just trying to give you a ball park idea. You will want to check with your local dealer for actual pricing.
Used tractors are certainly less money, but they aren't always a better value. Resale is strong, so prices tend to stay up. Much more so than a car or pickup. But if you buy a used tractor from a private party you pay no tax, and you allow that first buyer to take the bulk of the depreciation hit. It's worth considering and you can get a pretty decent used CUT for $10k.