I have owned Massey Ferguson, New Holland, and two John Deeres.
It is just as important to let folks know about tractors you don't like as the ones you do.
I never had to do much to the Massey but had a dealer in the next county where I could buy parts. The onl part I sourced through the dealer was a power steering pump seal I probably could have sourced elsewhere for less money.
My New Holland is an industrial backhoe. I have done a lot of work to. No local dealer. Initially parts were easy to look up online and eventually a member of another forum provided quality owner, service, and parts manuals in pdf. Half the parts are no longer available and have to be worked around or sourced outside their dealer system. New Holland has turned a great online parts system into a mess that you can't navigate. Messics still makes it possible but can't overcome the availability issue. One example is my 4wd solenoid. It apparently is not uncommon for the coil to burn up. New Holland no longer sells it separate from the $500+ solenoid. I eventually dug around and sourced the identical coil less the connector for under $20. Another issue is cylinder rebuild kits. They often changed internal components with good documentation. The last cylinder I rebuilt I ordered 3 possible kits for so I would have what I needed on hand. Not ONE kit had the correct wiper seal. One of the 3 kits had most of the seals I needed but I had to measure and order a wiper seal by size. I have gone through similar issues with EVERY cylinder I have rebuilt.
Both of my John Deere tractors have been dead on reliable. We have a dealer in any direction. They have a great online parts lookup system and provide free downloads for owners manuals. One of our faithful TBN members has a good stash of service manuals.
If I were to buy another tractor my preference would be a John Deere.