I think they are stout tractors. I have a 1010, which is of course not nearly as much tractor, but I really like mine. I do know one guy with a 1020 that broke the front axle, but I think it was through not paying attention.
The diesel engine is Toyosha, and the tractor itself was likely made for MF by Hinomoto as my 1010 was.
On the 1010, I've noted the following which I will pass along to you in case the 1020 is similar:
Many parts are still available, some are not.
I broke the round gearshift bushing (the ball around the gearshift lever inside the trans) by shifting too hard. Took me a while to find a replacement, which turned out to be plastic. Lesson learned.
The glowplugs on the 1010 don't do any heating at all for the first 10 seconds. Hit them for 20 and it'll fire right up.
Radiator fins can easily get clogged with chaff if you're mowing. Keep it clean.
I installed an $8.00 Radio Shack relay on the firewall after I discovered the starting circuit with the ignition and clutch safety switch was losing voltage along the way. Now the wire coming from the safety switch trips the relay instead of trying to start the tractor, and the relay switches current directly from the battery connection on the starter to the starter itself. No more cranking issues.
You can probably get all the filters you need from NAPA as I did. For some reason, they have a cross reference for the 1010.
You may want to get an I&T service manual for it. They are pretty cheap and give you enough information to see how things work.
Enjoy your 1020!