I don't think you can get better quality and refinement than Kubota. It will probably last forever.
I looked long and hard at both Mahindra and Kubota. In the size I wanted Kubota was more refined and proven. Mahindra had a poor dealer network and the hydraulics were variable between the same models at different dealers, some stronger, some weaker.
Look at the servicing requirements on each. I found it was difficult to check the oil on the Mahindra. In the size I wanted, the Kubota was not rated for a heavy duty front end loader because it's frame was lighter. After asking some Mahindra mechanics I found that, once in a while, they saw a front axle problem.
I found New Holland to be the toughest design and easiest to operate. It just fits me and I love driving it. It has done an amazing amount of work, but it has plastic fenders. So it's all a compromise.
Which one is the most fun to drive? Which transmission makes the most sense to you? How's the layout for the driver? How close is the dealer? Are they willing to deal? What buckets and backhoes are available and at what cost?
Now after over 500 hours of tough use in construction, with a backhoe and doing road work, my NH is fine and I would buy it again. I do think Mahindras are nice and their hearts are in the right place, as a company, but I'd probably pick one of the others.