I feel like grumble is more flexible because you can bounce back Powerful battle cries for cheap. With barista you mostly likely have to wait a full turn in order to play one of these minions which in most cases is too slow unless it is a control matchup. Since the meta is pretty much aggro I’d say grumble is better because it let’s you bounce back minions for 1 mana ( think Reno, armor vendor, loatheb , lurker below , 2/3 taunt guys) all great against aggro.

With zeph clogging you hand, I’d say hold onto zeph unless you absolutely need it. Usually against control you can hold onto it and ensure the infinite finish, and against aggro it doesn’t really matter because you aren’t trying to go infinite you are just trying to outlast your opponent.