User blog comment:Zilla4444/AD upgrade for Chalice of Harmony/@comment-5151680-20120610034731/@comment-3477331-20120610091336

If you buy a chalice and upgrade it to either one of these, any additional mana or mana regen you is worthless for everything of than archangel passive, manamune passive or these actives. Also I doubt you'll get to low amounts of mana in teamfightes, so the actives will often give you just a tiny little bit of bonus dmg.