I'm not 100% sure yet, but based off stat priorities I would put the Bite of the Bleeding Hollow over Xu'tenash. While it's 5 ilvls lower, it has double the mastery on it and crit over multi. Multi falls down a lot on the priority list after getting the set bonuses. I would put Xu'tenash over Bite if it were warforged though, due to 11 ilvls and it being a polearm over a staff for Elusive Brew.
I would hold the same answer for Mythic. Bite over Xu'tenash unless Xu'tenash is WF and Bite is not.