Actually, I don't think I have ever seen a stand-up moving mast reach truck in the US - only in Japan, but I am familiar with the NYK design.

There is plenty to argue as far as relative advantages of the pantograph vs moving mast reach truck design and since there is no real 'deep reach moving mast', I suppose that one could count it as an advantage of the pantograph style, as far as product range. However, that is driven by the market. With a lack of double deep racking in Western Europe, as compared to North America, comes a lack of demand for a truck to service this racking.