I parked mine up across a slope over the weekend. I drove it to a point where I started to feel a bit uneasy, then got out and tried to manually tip it over. That is my standard scientific test.
With a fair amount of effort I was able to get a front tire slightly clear of the ground but the back remained very well planted with no sign of lifting. Pretty sure I would have been able to lift the whole Ranger diesel on that same slope front and rear so I was more than happy with that test.
There appears to be plenty of weight down low without compromising ground clearance too much because it is always a juggling act making them high enough to clear obstacles but maintain good stability at the same time. Having owned the Ranger for about 18 months and putting it on many slopey situations, my immediate feeling about the Kubota in the first couple of hours driving is that it definitely makes me feel more confident both sideways and up and down. Less body roll and swaying around with Kubota's stiffer suspension feels safer to me but the ride is still very good. The springs are significantly heavier on the kubota, even more that I would have expected considering the extra weight. The Kubota also has a front stabiliser bar where the ranger didn't so that would also help I would imagine.
I think that the Ranger Diesel although marketed as a work utility, it still had more of a trail driving chassis and suspension which gave great ride but by comparison with the Kubota, felt a bit less stable having to turn across any decent slopes. My wife also commented on how stable the Kubota felt.
