define-key versus evil-define-key

Hi! What’s the preferred way of adding keys to a given mode’s map? Is (define-key evil-motion-state-local-map "\C-b" 'calendar-scroll-right-three-months) or (evil-define-key 'motion calendar-mode-map "\C-b" 'calendar-scroll-right-three-months) preferable? (From an ease-of-use perspective, the second is better, as it allows you to easily map more keys, but I’m wondering from a “the right way to do it” perspective.)