con1965 & white, welcome to both of you.
Like "white" I use a
B2910 which is essentially the older version of the new
B3030.
Here is what I see. The
L2800 is probably the worst tractor offered by Kubota, some people like it, I would recommend people to buy a different brand rather than that machine. I think the transmission/pto combination is a horrible choice for mowing work. Its absolute lack of mechanical sophistication compared to the other machines you are looking at simply takes it out of their league.
The
B3030 is the lightweight tractor champion in terms of size, weight and manuverability in that horsepower class. That light weight and small size mean its has limited capabilities in some areas, it simply does not have the capacity of some other tractors of this horsepower, but it excels in tasks that do not require heavy weight. For a mowing tractor it cannot be beat. It will very easily handle a snow blower, the loader is modest but powerful enough for most any homeowner tasks.
The
L3130 is a brute in comparison, in the roughly 30hp class of tractors it is about as tough as they come, its big, heavy and has lots of capacity. It will not fit into places that a
B3030 will fit into, but as you don't have many trees that might not be an issue at all. Can you mow with it? Sure. But at 1500+# heavier, do you really want to if you don't need the extra capacity? Now if you need the capacity, then it is a good choice, but I'd prefer the
B3030 if most of my tasks were mowing.