Rather than label an entire manufacturer's product line as "junk," a better term might be how trustworthy a brand is. I think everyone acknowledges JD and Kubota are extremely trustworthy (there are other brands too, especially as you get into large Ag tractors, but I think we're primarily referring to utility and compact and sub-compact tractors here). What I mean by "trustworthy" has nothing to do necessarily with reliability or durability...but rather the likelihood that the brand will remain in business indefinitely and will have parts available almost indefinitely (especially Deere), and will have a very legitimate warranty and repair operation. Value brands have a certain likelihood of either merging, being bought out, name changes, and going out of business completely. Parts availability can be sketchy, dealer coverage can vary from great to weak to non-existent. And good luck with warranty after one brand gobbles up another when it comes to tractors or machinery in general.
There will be hundreds of people that will claim their value brand tractor is definitely not junk because they've owned it for years and many hours and it has done everything they wanted and had very little to nothing go wrong. And I believe them - so while their machines are not "junk" by any means, the brand they chose may well not be "trustworthy."
That said, if you look at Kioti vs Kubota, there is an incredible parallel between these two and the automaker Hyundai-Kia vs Honda / Toyota. In the case of the vehicles, Hyundai and Kia started out as very, very basic...overall poor quality but acceptable reliability, very cheap price, and a good warranty. Today they are fully competitive with the previously "premium" Japanese mainstream automakers Honda and Toyota. Maybe not in every way or every model, but quite competitive and priced nearly identically. Kioti has clearly tried very hard to emulate Kubota, by using the same color and offering similar models...but at a better price. The other thing Kioti has tried to do (similar to the Korean automakers vs the Japanese) is to offer more standard features. For example, on a given size tractor, a rear remote might be standard on the Kioti but optional on the Kubota. Deere is perhaps the worst value in the entire tractor market, charging more to begin with and making nearly everything optional, but has even better resale value than Kubota. I don't think its a bad thing if the value brands start offering more standard features, as eventually this puts pressure on the major brands to do the same.
As a final note, its worth noting there are plenty of Chinese parts on the "premium" brands. Heck, a number of Deere tractors are made in India, same as Mahindra. I noticed the lift cylinders on the front end loader of my brand new 60HP Kubota have "China" stamped into them. I noticed the very expensive hydraulic and HST transmission filters of Kubota tractors are made in China, although the quality appears to be very good.
For me, I'm still buying a Kubota or Deere, because they are more trustworthy and - in my opinion - an overall better tractor. But its a free country, buy whatever you like.