Today is Hoshana Rabbah, which seems to be a hybrid of Yom Tov/Yomim Noraim/Chol Hamoed. For example, we daven the yom tov davening for shachris. However, we can do melacha like Chol Hamoed. To top it off, the chazzan wears a kittel and we say the 13 attributes by krias hatorah.
The question I have is regarding the tefilos we say after Mussaf Shemoneh Esray, beginning with Ein Keloheinu. These tefillos said on a weekday (which is what we say on Chol Hamoed) differ from those said after Mussaf on Yom Tov or Shabbos.
Which one do we say (were we supposed to say) today?