For anybody else considering these two machines here is my 2 cents.
I did the same shopping around when deciding to purchase a tractor and I ended up with the B2920
Anyways the JD2520 is more comparable to a B2630 or the newer B3200 or B3030 in size. Tires are larger and capacities including loader bucket width are larger.
Test drove the JD2520 and loved the dual touch pedals. Don't hate the rocker on the Kubota.