Soundguy -- can you buy parts for your New Holland at Tractor Supply? I know that with the exception of very basic 3PH parts like pins a top links, I can't buy parts for my Kubota there.
They do have some parts for olrder gas-powered tractors like the Ford 8N's, but that is about it. There are just too many different tractors out there for them to carry parts for all of them. For that matter, even Messick's has had to order many of the parts that I have needed for my Kubotas.
My point, and the point of other posters, is that parts availability at TSC is probably isn't a good benchmark. The benchmark should be, will parts be readily available at a local dealer, or some online source.
For example, Hoye Tractor (and I'm sure others) is a great source for parts for Yanmar tractors that are 20-30 years old, both officially imported, and grey-market.
Personally, I'd be more concerned about the quality of anything coming out of China, vs. Japan or Korea. I would certainly stick with one of the more major manufactures, vs. a Jimna, or any of the other Chinese-built units.
I know that from my research into some of the Chinese-made clones of the single-cylinder air-cooled Yanmar diesel engines, many reviewers stated that they needed to disassemble the engines, and clean sand our of them, and some even had to touch-up on the machining work, before they had an engine that would run well, and not destroy itself prematurely (due to the sand). They also commented on loose/improperly torqued fastens, such as head bolts
Brands that I would consider, based on my research of this and other forums, and also word-of-mouth (in no particular order):
Kubota
John Deere
Ford/New Holland
Case/IH
Allis Chalmers
Massey Ferguson
Yanmar
IMHO, I think your money is much better spent on a good-condition used tractor of one of the above brands (I'm sure there are several other's I have omitted) vs. a Chinese tractor.
That said, if you do go Chinese, the Jimna seem to be better known, and you'll probably find more help on this and other forums than with some of the others.