Using Whole milk here... Trickle Springs Creamery.
My Kefir is propagating RAPIDLY in this stuff... half a cup (2 1/4 cup batches, 4 days) and it's doubled in bulk. Tasted the first batch, it's decent; I'm drinking the second. Slightly sour but not "bad" or "rotten," definitely alcoholic but can't be more than 1%, fermented for 2 days at room temperature.
I'm having no trouble drinking this stuff... once the grains have grown enough, I'll be able to do 1/2 gallon or so batches, maybe fridge batches so I have some to drink throughout the week. Double-ferment: Ferment, strain into new container, put back into the fridge.
I must admit I find chilled Lassi and fresh milk tastier though. This stuff has a chalky aftertaste; also I think I'd prefer it more chilled.