I use a soup bowl that I got from a chinese restaurant! Palm-sized, ceramic, with just enough heft to it. I asked if I could buy one and they gave it to me free (I'm a regular there).
Too much heft in a bowl and it would be apain to hold while building lather.
I also use a mug warmer for heat and the ceramic bowl heats up in a relatively quick time and keeps that heat.
"There are some things which cannot be learned quickly, and time, which is all we have, must be paid heavily for their acquiring. They are simple things, and because it takes a man's life to know them, the little new that each man gets from life is very costly and the only heritage he has to leave".-E. Hemingway]