Curiosity having gotten the better of me, I got a pint of "regular" milk just to experiment with. The difference was immediately apparent. It was easy to get a good microfoam. The pour? Well I didn't exactly make "art" but I was able to build the base and "float" something resembling a design on the surface whereas with the soy, it would simply disappear or make some foamy blobs. I could probably make art with practice but I'm not going to buy any more dairy milk. I'll try some of the "barista" versions of the alternative milks and see if they work any better. Oat milk is out as it contains gluten which I also have to avoid.