I used to use normal cow’s milk, but currently I’m using Bonsoy, recommended by a friend. The first time I tried bonsoy I thought it was nearly as good as cow’s milk. Now that my taste buds have adjusted to Bonsoy, cow’s milk tastes weird (sour).
Oat milk tastes ok but doesn’t froth well. The interesting thing about Bonsoy is that it doesn’t have any added oil, and despite being quite low in fat, it still produces excellent foam. Aldi’s soy milk is not bad as a cheap substitute for Bonsoy, and Vitasoy is OK. I’m not a fan of almond milk. Haven’t tried anything else.
I was using 2%, but then switched to full cream because I heard it steams better. But I think I'll go back to 2%. I use UHT because it lasts longer open in the fridge and forever in the cupboard.