Oh heck Japon, that's a tough question. I would say they dislike both, equally.....:(

Wind tolerance depends on the leaf shape, more than anything else. A tree with more compact, star-shaped, fat-lobed leaves will take more wind than one of the feathery cultivars. Sun tolerance depends on the leaf color more. Purple, variegated, or golden varieties take less sun than plain green ones, or those with a moderate reddish tint. So a purple, star-leaved variety would like sun less, while a dissected purple-leaf variety couldn't decide. : )

Semi-shade, but as long as out of wind, they and kept watered, they will do well in direct sun. If kept in semi-shade then less watering is required. As Tugbrethil has said, it is wind that does all the damage.

that may be true north of Watford, Kildermorie, but here in London, japanese Acers need protection from hot sun between 11 and 3 in high summer or they get fried to a crispy brown frazzle.