Board Thread:Questions and Answers/@comment-4310945-20140425001334/@comment-26091912-20151226110044

At this point, Yhwach is already so OP, that his power literally exceeds 'power'. And he's only going to become stronger and stronger. Aizen maybe ridiculously strong too, but The Almighty can negate everything, so I'd say what MilanVukas said, but I'd Yhwach would win, because given what he's been able to do so far, he'd find a way to nullify or even absorb the Hogyoku, thus leaving Aizen vulnerable and eventually defeating him.