I have the opposite issue I started with Milk and I'm too afraid to use water incase I don't like it and find I have to stick to milk.
I'm more concerned because I'm currently using Strawberry which is on version 4.0 - with the massive sugar increase that comes with 5.0 plus the addition of the sugar in the milk, it's a little concerning.
Anyway, to answer it tastes perfectly fine with milk. I've only tried Huel and Queal, to me, Huel is undrinkable.