Assuming the OP has done his research and is happy with either tractor at whatever price they are at, I wouldn't worry about a tractor sitting in a dry crate for months. I would look at it carefully for water damage, and getting into somewhere its not supposed to be. If that's fine and he wants the Kubota, then he should get it.
The tractors are pretty much equal for specs, but usually Kioti includes a few grand of features that are options on a Kubota.
When I bought my tractor, the near equal weight and equipped Kubota was around 25-30% more, and I was a very small fish in a Kubota dealerships net, so they were just offering MSRP, plus plus plus for anything.
The Kioti dealer I bought from was the opposite, gave me his best/fair price up front and added a second remote for the cost of parts, filled the rear tires, setup a hyd top link, and a delivered with a full tank of fuel. 1 remote, hitch and bar, telescopic 3 pt arms, pin sway control, ssqa, rear 3pt control, rubber floor mat, loader control beside the seat, all included.
The difference in price back then, invested for all this time, is getting close to buying a new tractor, and is much more than the resale difference between the two brands.