Dunno about sunglasses but with snowboard goggles ... there is a world of difference between £50 Cebe goggles and £150 Oakley goggles - better visibility, fit etc.
... but for running... I've got a pair of £50 Julbo glasses, stay on fine, dunno about the visibility as I only ever wear sunlasses on top of my head to keep the hair out ofmy eyes, heaven forbid that I'd use them for their proper purpose...