Vegetables grow best in full light so avoid shade as much as possible. I think the Victorian idea of whitewashing glass to lessen summer heat in sheltered gardens has given the wrong impression about shade being somehow desirable for growth, except for certain ornamental plants.
More important than orientation is easy access, with doorways situated closest to point of entry in a garden or field, and slope plays a part too: I would prefer to be lined, lengthways, up and down rather than across a slope. Orientation comes third after that, north-south is recommended if you grow tall plants, so their shade is more evenly distributed, also so that summer sun is less intense with midday sun running along a structure instead of lighting it side on, more powerfully, on an east-west structure. However I have two tunnels lined up in each sense and the east-west one does not overheat at midday, as it has large doors for ventilation, which are standard.