My preference would be the Hyster. Number 1 is that it has a 5000# base capacity and the Komatsu is 4000#. Even at a base capacity of 5000# if the Hyster is equipped with the triple mast and a side shifter, the net capacity could drop to 3,700#.
Komatsu seems to be winding down in the US. According to their website they only have factory owned branches in major cities. They seem to rely on sales to national rental houses.
I think that the resale value would be much higher on the Hyster and parts availability should be better.