I don't think I've never seen a "short tub" dishwasher in all my life if I exclude the old machines seen here!
I've seen "standard tub" machines, where the door is as long as the front, for 82 cm (standard undercounter height) and "tall tub" at 87 to 90 cm in dishwashers designed to be built-in in "modern" kitchens that have "oversize" counters to hold them.
It's the first time I'm listening to such a thing that "short tub" machines are more reliable than "tall tub" ones, to me the guy told you a completely untrue lie, not very professional!
And think that if you're going to get a short tub machine you're never going to put in 33-34 cm plates or serving trays in them, thing that you can easily do in any bigger tub dishwasher!