We have a highish housed 3120, they pull like a train with a bombproof engine, a very well balanced tractor that used to run a 5furrow plough and press and a 3m combi, very good on draft work, now semi retired to spraying and row crop work. Dynashift is excellent, go steady with the long gear sticks and it shouldn't give much bother in that department loads of gears and 40k. There getting on in age and could be a few electric gremlins in the computer packs that works the hydraulics, ours seems to drink wd40 but seems to cure it after a good spray. It hasn't been without its problems it is on its 4th backend oil pump, think its had the brakes pushed through it early in its life by enthusiastic potato leaders which has done it no favours.
Just my experiences of them, not sure on the other tractors you've mentioned as I don't really take an interest in them
Just my experiences of them, not sure on the other tractors you've mentioned as I don't really take an interest in them