I have a 6500 4WD that I bought new a year ago. Only "problem" was that one valve connection on the loader joystick loosened up and I had to remove the boot and retighten. Total cost, one narrow snap tie out of my big bag (3 cents, maybe). I got the Mahindra because: a) great dealer close by with good local reputation for service; b) best power/weight for the buck (similar orange was 35% more and similar green was over 50% more); savings allowed me to get skid-compatible QA FEL, forks, bale spear, and canopy and still be less than the bare bones K or JD.
My place is pretty hilly and I have the tires fluid filled and set the widest they will go. I'm in small scale hay production with a 7' belt-drive sickle bar mower, used 9' tedder, 11' 5-wheel rake, and a very temprimental IH 46 (1957 model) baler. My little A-C can handle the tedder, and might handle the mower and rake (with some difficulty) but has no chance with the baler. The Mahindra pulls/powers with no problem on our hills and is heavy enough to soak up the baler ram shock as well.
All the majors make pretty good tractors in this size range, but if you have a good dealer fairly close, I don't think you can beat Mahindra for the money.