I think it mostly comes down to any Dex save abilities that involve both damage to trigger these features AND some other type of effect on a failed save like being restrained. In those situations (if there are any) Enhanced Vitality might be the better option if you're built for it, otherwise...
Assuming it's drawn into the artwork like I think on T'lingbet's right shoulder (and there are real world examples of this) it looks like a shoulder strapped/mounted shield. It's effectively like a having an unusually large pauldron on one side.